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<h1 id="widgets">Widgets 1.0: The Widget Landscape (Q1 2008)</h1>

<h2 class="no-num no-toc" id="editors">W3C Working Draft 14 April 2008</h2>

<dl>
<dt>This version:</dt>

<dd><a href=
"http://www.w3.org/TR/2008/WD-widgets-land-20080414/">http://www.w3.org/TR/2008/WD-widgets-land-20080414/</a></dd>

<dt>Latest version:</dt>

<dd><a href=
"http://www.w3.org/TR/widgets-land/">http://www.w3.org/TR/widgets-land/</a></dd>

<dt>Latest Editor's Draft:</dt>

<dd><a href=
"http://dev.w3.org/2006/waf/widgets-land/">http://dev.w3.org/2006/waf/widgets-land/</a></dd>

<dt>Previous version:</dt>

<dd>none.</dd>

<dt>Version history:</dt>

<dd>Twitter messages (non-editorial changes only): <a href=
"http://twitter.com/widgetspecs">http://twitter.com/widgetspecs</a> (<a href=
"http://twitter.com/statuses/user_timeline/14349303.rss">RSS</a>)</dd>

<dt>Editor:</dt>

<dd><a href="http://datadriven.com.au/">Marcos Caceres</a>, Invited Expert</dd>
</dl><!--begin-copyright-->

<p class="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright"
rel="license">Copyright</a> &copy; 2008 <a href="http://www.w3.org/"><acronym title=
"World Wide Web Consortium">W3C</acronym></a><sup>&reg;</sup> (<a href=
"http://www.csail.mit.edu/"><acronym title=
"Massachusetts Institute of Technology">MIT</acronym></a>, <a href=
"http://www.ercim.org/"><acronym title=
"European Research Consortium for Informatics and Mathematics">ERCIM</acronym></a>,
<a href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C <a href=
"http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>, <a href=
"http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and <a href=
"http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> rules
apply.</p><!--end-copyright-->
</div>
<hr />

<h2 class="no-toc no-num" id="abstract">Abstract</h2>

<p>This document surveys a group of market-leading widget user agents with the aim to
inform the requirements of the <cite>Widgets 1.0: Requirements</cite> document. The
survey exposes commonalities and fragmentation across widget user agents, and discusses
how fragmentation currently affects, amongst other things, authoring, security,
distribution and deployment, internationalisation and the device-independence of widgets.
The document concludes by making a set of recommendations on what aspects of widgets
require standardization to reduce fragmentation to ultimately standardize a
cross-platform widget solution.</p>

<h2 class="no-num no-toc" id="sotd">Status of this Document</h2>

<p><em>This section describes the status of this document at the time of its publication.
Other documents may supersede this document. A list of current W3C publications and the
latest revision of this technical report can be found in the <a href=
"http://www.w3.org/TR/">W3C technical reports index</a> at
http://www.w3.org/TR/.</em></p>

<p>This is the <a href="http://www.w3.org/2005/10/Process-20051014/tr.html#first-wd">W3C
First Public Working Draft</a> of the <em>Widgets 1.0: Landscape</em>. Once all the
comments about this document will have been addressed, the Working Group intends to
publish a final version of this document as a <a href=
"http://www.w3.org/2005/10/Process-20051014/tr.html#q75">W3C Working Group Note</a>.</p>

<p>The W3C Membership and other interested parties are invited to send comments to
<a href="mailto:public-appformats@w3.org">public-appformats@w3.org</a>, the W3C's public
email list for issues related to Web Application Formats. <a href=
"http://lists.w3.org/Archives/Public/public-appformats/">Archives</a> of the list are
available.</p>

<p>This document is produced by the <a href="http://www.w3.org/2006/appformats/">Web
Application Formats WG</a>, part of the <a href=
"http://www.w3.org/2006/rwc/Activity">Rich Web Clients Activity</a> in the W3C <a href=
"http://www.w3.org/Interaction/">Interaction Domain</a>. It is expected that this
document will become a Working Group Note. Publication as a Working Draft does not imply
endorsement by the W3C Membership. This is a draft document and may be updated, replaced
or obsoleted by other documents at any time. It is inappropriate to cite this document as
other than work in progress.
<!-- Several Working Drafts for this Note were available for review; the material in this document was subject to a public last call. At the time of publication, the Working Group has no specific plans to further revise this document. --></p>

<p>This document was produced by a group operating under the <a href=
"http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February 2004 W3C Patent
Policy</a>. W3C maintains a <a href="http://www.w3.org/2004/01/pp-impl/38483/status" rel=
"disclosure">public list of any patent disclosures</a> made in connection with the
deliverables of the group; that page also includes instructions for disclosing a patent.
An individual who has actual knowledge of a patent which the individual believes contains
<a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential
Claim(s)</a> must disclose the information in accordance with <a href=
"http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section 6 of the
W3C Patent Policy</a>.</p>

<h2 class="no-toc no-num" id="table">Table of Contents</h2><!--begin-toc-->

<ul class="toc">
<li>
<a href="#introduction"><span class="secno">1.</span> Introduction</a>

<ul class="toc">
<li><a href="#purpose"><span class="secno">1.1</span> Purpose</a></li>
</ul>
</li>

<li><a href="#terms"><span class="secno">2.</span> Terms</a></li>

<li>
<a href="#widgets0"><span class="secno">3.</span> Widgets and Widget User Agents</a>

<ul class="toc">
<li><a href="#differences"><span class="secno">3.1</span> Differences from Web
Widgets</a></li>

<li><a href="#differences0"><span class="secno">3.2</span> Differences from Java
Applets</a></li>
</ul>
</li>

<li>
<a href="#packaging"><span class="secno">4.</span> Packaging for Distribution and
Deployment</a>

<ul class="toc">
<li><a href="#packaging0"><span class="secno">4.1</span> Packaging Formats, file
extensions and Media Types</a></li>
</ul>
</li>

<li>
<a href="#metadata"><span class="secno">5.</span> Metadata and Configuration</a>

<ul class="toc">
<li>
<a href="#metadata0"><span class="secno">5.1</span> Metadata</a>

<ul class="toc">
<li><a href="#fragmentation"><span class="secno">5.1.1</span> Fragmentation
Issues</a></li>
</ul>
</li>
</ul>
</li>

<li>
<a href="#authoring"><span class="secno">6.</span> Authoring and Scripting</a>

<ul class="toc">
<li><a href="#apis"><span class="secno">6.1</span> APIs</a></li>

<li><a href="#widget"><span class="secno">6.2</span> Widget object: properties and
events</a></li>
</ul>
</li>

<li><a href="#user-interface"><span class="secno">7.</span> User interface and
Accessibility</a></li>

<li><a href="#instantiation"><span class="secno">8.</span> Instantiation</a></li>

<li><a href="#i18n"><span class="secno">9.</span> Internationalization and
Localization</a></li>

<li><a href="#digital"><span class="secno">10.</span> Digital Signatures</a></li>

<li><a href="#automatic"><span class="secno">11.</span> Automatic Updates</a></li>

<li><a href="#device"><span class="secno">12.</span> Device Independence</a></li>

<li><a href="#security"><span class="secno">13.</span> Security Models</a></li>

<li><a href="#icons"><span class="secno">14.</span> Icons</a></li>

<li><a href="#standardizable"><span class="secno">15.</span> Standardizable Aspects of
Widgets</a></li>

<li class="no-num"><a href="#acknowledgments">Acknowledgments</a></li>

<li class="no-num">
<a href="#references">References</a>

<ul class="toc">
<li class="no-num"><a href="#related">Related Sources</a></li>
</ul>
</li>
</ul><!--end-toc-->

<h2 id="introduction"><span class="secno">1.</span> Introduction</h2>

<p>This document surveys the widget landscape by examining how <a href=
"#market-leading">market-leading widget user agents</a> address issues around:</p>

<ul>
<li>distribution and deployment,</li>

<li>metadata and configuration,</li>

<li>user interface and accessibility,</li>

<li>authoring,</li>

<li>internationalization and localization,</li>

<li>device-independence,</li>

<li>Initialization,</li>

<li>automatic updates,</li>

<li>and security.</li>
</ul>

<p>The <span><dfn id="market-leading">market-leading widget user agents</dfn></span> that
are included in the survey are listed below. The <a href="#widget2">widget user
agent</a>s were subjectively chosen because of their perceived prevalence in the
<span>market place. This survey was conducted independently of any vendor</span> and no
vendor explicitly requested they be included in the survey.</p>

<table cellspacing="0" summary="">
<caption>
Market-Leading Widget User Agents
</caption>

<thead>
<tr>
<th>Widget User Agent</th>

<th>Vendor</th>

<th>Version</th>

<th>Platform</th>
</tr>
</thead>

<tfoot>
<tr>
<th>Widget User Agent</th>

<th>Vendor</th>

<th>Version</th>

<th>Platform</th>
</tr>
</tfoot>

<tbody>
<tr>
<td><dfn id="konfabulator">Konfabulator</dfn></td>

<td>Yahoo!</td>

<td>4.5</td>

<td>Windows XP, Windows Vista, MacOS</td>
</tr>

<tr>
<td><dfn id="windows">Windows Sidebar</dfn></td>

<td>Microsoft</td>

<td>1.0</td>

<td>Windows Vista</td>
</tr>

<tr>
<td><dfn id="google">Google Desktop Gadgets</dfn></td>

<td>Google</td>

<td>1.x</td>

<td>Windows XP, Windows Vista</td>
</tr>

<tr>
<td><dfn id="opera">Opera Widgets</dfn></td>

<td>Opera</td>

<td>9.5 Beta</td>

<td>Mac OS 10.5, Windows XP, Windows Vista</td>
</tr>

<tr>
<td><dfn id="dashboard">Dashboard</dfn></td>

<td>Apple</td>

<td>1.1</td>

<td>Mac OS 10.5</td>
</tr>

<tr>
<td><dfn id="web-runtime">Web-Runtime</dfn></td>

<td>Nokia</td>

<td>1.0 Beta</td>

<td>S60 3rd Edition, Feature Pack 2 (emulator)</td>
</tr>

<tr>
<td><dfn id="joost">Joost Widgets</dfn></td>

<td>Joost</td>

<td>1.0 Beta</td>

<td>Mac OS 10.5, Windows XP, Windows Vista</td>
</tr>
</tbody>
</table>

<p class="redNote"><strong>The inclusion of the widget user agents in this survey does
not indicate endorsement of the standardization process by any particular vendor (in
other words, just because a widget user agent appears should not be taken to mean that
they will implement any part of the Widgets 1.0 specifications).</strong></p>

<h3 id="purpose"><span class="secno">1.1</span> Purpose</h3>

<p>The purpose of this document is to provide a holistic overview of the <dfn id=
"widget0">widget space</dfn> and provide information to aid in standardization process of
widgets by the <a href="http://www.w3.org/2006/appformats/">Web Application Formats
Working Group</a>. As such, this document provides:</p>

<ul>
<li>A consistent set of terms that can be used throughout the standardization process,
including in specifications.</li>

<li>A definition of what constitutes a widget and a widget user agent for the sake of
standardization (and what does not constitute a widget).</li>

<li>A discussion of what role various technologies play in the lifecycle of a
widget.</li>

<li>Comparison matrices that clearly demonstrate fragmentation and interoperability
across the widget landscape.</li>

<li>A list of standardizable aspects of widgets.</li>
</ul>

<h2 id="terms"><span class="secno">2.</span> Terms</h2>

<p>This section defines some of the key terms related to widgets.</p>

<dl>
<dt><dfn id="widget1">Widget</dfn>:</dt>

<dd>For the purpose of this standardization process, a widget is an end-user's
conceptualization of an interactive single purpose application for displaying and/or
updating local data or data on the Web, packaged in a way to allow a single download and
installation on a user's machine or mobile device. A widget may run as a stand alone
application (meaning it can run outside of a Web browser), or may be embedded into a Web
document. In this document, the runtime environment on which a widget is run is referred
to as a widget user agent and a running widget is referred to as an instantiated widget.
Prior to instantiation, a widget exists as a widget resource.</dd>

<dt><dfn id="widget2">Widget user agent</dfn>:</dt>

<dd>The user agent (software application) that hosts an instantiated widget. Generally
speaking, widget user agents are either directly built on, or provide similar
functionality to a Web browser. An increasing number are actually built directly on top
of Web browsers so they are able to process/render <cite><a href="#html">HTML</a></cite>
documents, while others incorporate Web browser components like ECMAScript interpreters.
widget user agents are built for many different software platforms and devices, including
Microsoft's Windows, Apple's MacOS, Symbian, Linux, and so on; and some widget user
agents, such as the Konfabulator and Opera Widgets, run on multiple platforms.</dd>

<dt><dfn id="instantiated">Instantiated widget</dfn>:</dt>

<dd>The runtime manifestation of a decompressed widget resource whose start file has been
instantiated on a widget user agent. The instantiated widget may have been configured
through a configuration document. The ability for an instantiated widget to be programmed
and behave interactively is provided via a widgets API.</dd>

<dt><dfn id="icon">Icon</dfn>:</dt>

<dd>An image or symbolic representation of an instantiated widget. Icons are usually used
to represent the widget in non-running context, such as menus and docks. Some widget user
agents, such as Konfabulator, allow authors to dynamically change the icon at runtime.
For example, a weather widget might update its icon as the weather or time of day
changes.</dd>

<dt><dfn id="widget3">Widget resource</dfn>:</dt>

<dd>A resource created from some packaging format that encapsulates the resources of a
widget for the purposes of distribution and deployment. On the wire, a widget resource is
identified by an arbitrary widget media type.</dd>

<dt><dfn id="media">Media type</dfn>:</dt>

<dd>An <cite><a href="#media">media type</a></cite> that formally associates a widget
resource with some proprietary widget user agent. For example, Joost's widget engines
requires that widgets be served over HTTP with a
<code>application/vnd.joost.joda-archive</code> media type.</dd>

<dt><dfn id="packaging1">Packaging format</dfn>:</dt>

<dd>The physical data format used to create a widget resource. For example, the flat-file
format described in the <cite><a href="#konfabulator0">Konfabulator Reference</a></cite>
or the <cite><a href="#zip">Zip</a></cite> file format supported by Opera Widgets and
Microsoft's Vista Sidebar.</dd>

<dt><dfn id="resource">Resource:</dfn></dt>

<dd>Any file or directory used by an instantiated widget that resides either inside a
widget resource or is accessible over <cite><a href="#http"><abbr title=
"Hyper Text Transfer Protocol">HTTP</abbr></a></cite>. In a widget resource, resources
may be organized in directories and may have versions of those directories tailored for
localization purposes. Examples of resources include images, text, markup, style sheets,
executable scripts, and sounds.</dd>

<dt><dfn id="start">Start file</dfn>:</dt>

<dd>A resource either inside the widget resource or on the Web that when instantiated
represents the widget. If an instantiated widget contains a configuration document, the
widget user agent may configure the start file through that configuration document.</dd>

<dt><dfn id="configuration0">Configuration document</dfn>:</dt>

<dd>A distinguished resource where authors can declare metadata and/or configuration
parameters for a widget. A widget user agent uses a configuration document to configure a
widget upon instantiation. The configuration document may also define the relationship
between resources in the widget resource. The configuration document usually takes the
form of an <cite><a href="#xml"><abbr title=
"eXtensible Markup Language">XML</abbr></a></cite> file; for example, the
<code>config.xml</code> resource bundled with an Opera widget.</dd>

<dt><dfn id="metadata1">Metadata:</dfn></dt>

<dd>Data declared in the configuration document about a widget that relates to authorship
or classification, but does not affect the behavior of the widget at runtime (eg. the
author's name and email).</dd>

<dt><dfn id="configuration1">Configuration parameter</dfn>:</dt>

<dd>Any declaration in the configuration document that affords the widget with
functionality beyond its default behavior (eg. declaring that the widget will require
network access).</dd>

<dt>&nbsp;</dt>

<dt><dfn id="bootstrap">Bootstrap</dfn>:</dt>

<dd>A mechanism that either declaratively or automatically finds the start file in an
instantiated widget.</dd>

<dt><dfn id="widget4">Widget API</dfn>:</dt>

<dd>A set of programming interfaces that provide functionality specific to and
instantiated widget. Current APIs range extensively in the level of functionality they
provide an author; see for example Microsoft's <abbr title=
"Application Programming Interface">API</abbr> for accessing the operating system in the
<cite><a href="#sidebar">Sidebar Reference</a></cite>.</dd>
</dl>

<h2 id="widgets0"><span class="secno">3.</span> Widgets and Widget User Agents</h2>

<p>Since around 2003, a relatively new kind of application has seen significant
proliferation onto desktop computers and, more recently, web-enabled portable devices
like mobile phones. This kind of application is generally referred to by developers as a
<em>widget engine</em>: a piece of software that is able to run other smaller
applications known as <em>widgets</em> or <em>gadgets</em>. On the user's desktop,
widgets have gradually taken the place of some traditional single-purpose applications.
Typical examples of widgets range from simple clocks, CPU gauges, post-it notes, games,
battery-life indicators, to more sophisticated web-enabled widgets like weather
forecasters, news readers, email checkers, photo albums and currency converters.<br />
<br />
There are literally thousands of unique widgets available for download on the web, which
users generally collect to create personal widget inventories. These widget inventories
provide users with access to online services that they commonly use. This means that, in
a lot of instances, users don't need to open up a web browser to get the information that
they want (eg. to check the weather). This is an aspect of widgets that makes them
particularly attractive on mobile devices, where the monetary cost of downloading web
pages is currently an issue for many users.</p>

<p>For developers, some widgets differ from traditional binary applications in that they
are created using the same open technologies used to create web pages. Widget engines
mimic, in many ways, the behavior of web browsers: an increasing number are actually
built directly on top of web browsers so they are able to render web pages, while others
incorporate web browser components such as ECMAScript interpreters. To developers and
vendors, this means that most widgets are significantly easier to create than
applications developed with lower-level programming languages such as Java and C#.</p>

<p>Amidst the popular rise of widgets and widget engines lay a number of issues for
users, developers, current vendors and new vendors wanting to enter the market. By
surveying various aspects that pertain to widget user agents, this document discusses
these issues so they may be resolved through the W3C standardization process.</p>

<p>As shown in figure 1, a widget is instantiated on a widget user agent and can make use
of a number of technologies that serve a different role (eg. distribution and deployment,
etc). However, some of those technologies have not yet been formally standardized (items
marked with an asterisk), which has contributed to fragmentation across the widget
space.</p>

<div class="figure">
<p><img alt="Widget technology stack" height="384" src="figures/widget_arch.png" width=
"883" /></p>

<p><dfn id="figure">Figure 1</dfn>. A typical widget technology stack and aspects that
have require standardization. Please note that this technology stack is intended as a
guide, and does not represent the technology stack of any particular user agent.</p>
</div>

<h3 id="differences"><span class="secno">3.1</span> Differences from Web Widgets</h3>

<p><dfn id="web-widgets">Web widgets</dfn> (also known as <em>modules</em> or
<em>badges</em>) are fragments of <abbr title="HyperText Markup Language"><cite><a href=
"#html">HTML</a></cite></abbr>, <abbr title="Cascading Style Sheets"><cite><a href=
"#css">CSS</a></cite></abbr>, and <cite><a href="#ecmascript">ECMAScript</a></cite> (or
possibly an Adobe Flash movie) that are either declaratively or dynamically included into
a Web document. A common example of Web widgets is one that downloads a set of icon-sized
images from a photo-sharing Web site and displays those images as a slide-show based on a
set of user preferences (eg. the images tagged 'vacation Italy'); such Web widgets are
commonly seen embedded into social networking Web sites and blogs. Popular providers of
Web widgets include:</p>

<ul>
<li><a href="http://www.google.com/apis/gadgets/">Google Homepage Gadgets</a> (<a href=
"http://www.google.com/ig">iGoogle Gadgets</a>),</li>

<li><a href="http://widgets.wordpress.com/">WordPress Widgets</a>,</li>

<li>and <a href="http://microsoftgadgets.com/">Microsoft Live Gadgets</a>.</li>
</ul>

<p>Unlike widgets, Web widgets a hosted on the server-side and are embedded into HTML
documents prior to being served to the client. The creation of a Web widget usually
involves having an author specify, in XML or some other format (eg. PHP), what the widget
does and which APIs the Web widget depends on. This document is then uploaded to a
server, where when it is served to a client, it is transformed into HTML, CSS, and
ECMAScript. For example, the input column of the table below shows a typical iGoogle
gadget specification:</p>

<table>
<caption>
iGoogle Gadget Transformation Example
</caption>

<thead>
<tr>
<th>Input</th>

<th>Output</th>
</tr>
</thead>

<tfoot>
<tr>
<th>Input</th>

<th>Output</th>
</tr>
</tfoot>

<tbody>
<tr>
<td>
<pre>

&lt;?xml version="1.0" encoding="UTF-8"?&gt;<br />&lt;Module&gt;<br />&lt;ModulePrefs title="hello world example" /&gt;<br />&lt;Content type="html"&gt;&lt;![CDATA[<br />&lt;h1&gt;Hello, world!&lt;/h1&gt;<br />]]&gt;&lt;/Content&gt;<br />&lt;/Module&gt;
</pre>
</td>

<td>
<h1 class="no-toc no-num c1" id="hello">Hello World!</h1>
</td>
</tr>
</tbody>
</table>

<p>After being processed on the server-side, the code in the input column is transformed
to HTML, CSS, and ECMAScript and inserted into the served document as either an
<code>iframe</code> or as HTML elements (see the the Output column above). The actual
code that Google generates from the example is too large to be included in this
document.</p>

<h4 class="no-toc no-num" id="functional">Functional Differences</h4>

<p>Because Web widgets and a widget have a reliance of Web technologies, their offer much
of the same functionality. However, differences exist in:</p>

<ul>
<li>the packaging format,</li>

<li>the security model,</li>

<li>and the APIs.</li>
</ul>

<p>In relation to the packaging format , Web widgets are generally not packaged or
downloaded as a single file (except in the case of Adobe Flash movies). Instead, Web
widgets are commonly dynamically instantiated through a mix of <cite><a href=
"#ecmascript">ECMAScript</a></cite>, <abbr title=
"HyperText Markup Language"><cite><a href="#html">HTML</a></cite></abbr> elements, and
<abbr title="Cascading Style Sheets"><cite><a href="#css">CSS</a></cite></abbr>. However,
similar to a widget as described in this document, some Web widgets make use of a
dynamically loaded RSS file or <abbr title="JavaScript Object Notation"><cite><a href=
"#json">JSON</a></cite></abbr> as a configuration document format.</p>

<p>In relation to security models, unlike a widget, Web widgets are generally part of a
<abbr title="HyperText Markup Language"><cite><a href="#html">HTML</a></cite></abbr>
document's <abbr title="Document Object Model">DOM</abbr> and so are bound to all the
security constraints imposed by Web browsers.This means that Web widgets cannot make
cross-domain requests, cannot autonomously access resources on an end-user's device,
access system-level properties like the make, model, or usage percentage of the
<abbr title="central processing unit">CPU</abbr>, or execute system level commands like
creating or deleting files, while widgets that run on most market-leading widget user
agents generally can. In other words, some widget user agents provide a more relaxed
security model than the one afforded to Web widgets by Web browsers.</p>

<p>The ability for a widget to perform actions beyond the security scope of Web widgets
is partially afforded by widget-specific APIs. For example, on Windows Vista's Sidebar, a
widget can be scripted to create a new folder on the end-user's hard drive by calling
<code>'System.Shell.Folder.newFolder(strNewFolderName)'</code>. See Microsoft's
<cite><a href="#sidebar">Sidebar Reference</a></cite> or <cite><a href=
"#konfabulator0">Konfabulator Reference</a></cite> for more examples of API functionality
that is beyond the scope of Web widgets.</p>

<p>Another difference is how widget user agents handle internationalization when compared
to Web widgets (Web Browsers). On the Web, internationalization is sometimes handled
through <cite><a href="#http">HTTP</a></cite>'s <code>Accept-Language</code> header: this
works by allowing the Web Browser to send the end-user's preferred language to a server
(eg. <code>Accept-Language: en-us</code>). If the server contains a version of the
desired resource in the end-user's language of choice, then the localized resource may be
returned to the end-user. A widget, on the other hand, may sometimes contained all
localized resources inside the widget resource in folders named using the common
language-region pattern (eg. /en-us/). When the widget is instantiated, the widget user
agent attempts to match one of these specially named folders to user's language
preferences. See the <a href="#i18n">Internationalization and Localization</a> section
for more information.</p>

<h3 id="differences0"><span class="secno">3.2</span> Differences from Java Applets</h3>

<p>Widgets and Java applets share many commonalities. For instance, both widgets and
applets rely on a pre-installed runtime engine for execution: java applets rely on the
presence of the Java Runtime Environment (JRE), while widgets rely on the presence of
their target widget engine. Widget and Java applets also share many similar functional
aspects, like being able to do asynchronous HTTP requests to download resources from the
Web.</p>

<p>It is argued that the most notable difference between them is that widgets are easier
for authors to create than Java applets. This argument is made because widgets are
created using HTML, CSS, and ECMAScript, which have very forgiving error handling and a
short learning curve compared to Java. Another difference is that Java Applets are
intended to run inside Web pages, while widgets as described in this document generally
serve the purpose of stand-alone applications that run outside of a Web browser.</p>

<h2 id="packaging"><span class="secno">4.</span> Packaging for Distribution and
Deployment</h2>

<p><dfn id="packaging2">Packaging</dfn> refers to encapsulating all the necessary
resources and metadata required by the widget into a single file for the purpose of
distribution and deployment. <dfn id="distribution">Distribution and deployment</dfn>
refers to getting a widget from the Web to run on an user's device as easily as
possible.</p>

<h3 id="packaging0"><span class="secno">4.1</span> Packaging Formats, file extensions and
Media Types</h3>

<p>The <em>de facto</em> standard for packaging widgets is the Zip file format, but with
vendors requesting that their developers use a vendor specified file extension (ie. not
.zip, but .widget, or .gadget, etc) when packaging their widgets.</p>

<p>Once a widget has been packaged for distribution, it is put onto a web server and
served with an appropriate media type. The purpose of a media type is to allow a browser,
for instance, to automatically associate a widget resource with the appropriate widget
user agent. For example, widgets served for Operas widget engine are served with the
<code>application/x-opera-widgets</code> media type and associated with the Opera
browser. If a widget engine has correctly registered itself with the operatig system to
be the program of choice to deal with a particular media type media type and/or file
extension with, the web browser should automatically pass widgets to the widget engine
without the end-user having to select the widget resource manually.</p>

<p>End-users generally acquire widget resources directly from vendors (eg. Apple, Yahoo!)
who often host dedicated online galleries where users can search for widgets and where
developers can submit or update widgets they have created. However, authors are free to
distribute their widgets from their own web sites.</p>

<dl>
<dt>Packaging Format</dt>

<dd>The <a href="#packaging1">packaging format</a> is supported <a href="#widget2">widget
user agent</a>.</dd>

<dt>Compression</dt>

<dd>The compressions algorithm supported by the widget user agent.</dd>

<dt>File extension</dt>

<dd>The file extensions that associates a widget with a widget user agent.</dd>

<dt>Media type</dt>

<dd><span class="backMatter">As widgets are generally distributed via the Web, vendors
usually assign them an arbitrary MIME type. The MIME type, which is usually used in
conjunction with the file extension, helps a <a href="#widget2">widget user agent</a>
associate the a widget with the appropriate <a href="#widget2">widget user
agent</a>.</span></dd>
</dl>

<table cellspacing="0" summary="">
<caption>
Packaging Formats, file extensions and Media Types
</caption>

<thead>
<tr>
<th>Widget User Agent</th>

<th>Packaging Format</th>

<th>Compression</th>

<th>File Extension</th>

<th>Media type</th>
</tr>
</thead>

<tfoot>
<tr>
<th>Widget User Agent</th>

<th>Packaging Format</th>

<th>Compression</th>

<th>File Extension</th>

<th>Media type</th>
</tr>
</tfoot>

<tbody>
<tr>
<td>Konfabulator</td>

<td>Proprietary flat-file, Zip</td>

<td>Deflate (Zip)</td>

<td>.widget (not enforced)</td>

<td><code>application/vnd.yahoo.widget</code></td>
</tr>

<tr>
<td>Windows Sidebar</td>

<td>Zip, Cab, directory</td>

<td>Deflate</td>

<td>.gadget</td>

<td><code>application/x-windows-gadget</code></td>
</tr>

<tr>
<td>Google Desktop</td>

<td>Zip</td>

<td>Deflate</td>

<td>.gg</td>

<td><code>app/gg</code></td>
</tr>

<tr>
<td>Opera Browser</td>

<td>Zip</td>

<td>Deflate</td>

<td>.zip</td>

<td><code>application/x-opera-widgets</code></td>
</tr>

<tr>
<td>Apple Dashboard</td>

<td>Zip</td>

<td>Deflate</td>

<td>.wdgt or .zip</td>

<td><code>application/x-macbinary</code></td>
</tr>

<tr>
<td>Nokia Web-Runtime</td>

<td>Zip</td>

<td>Deflate</td>

<td>.wgz</td>

<td><code>application/x-nokia-widgets</code></td>
</tr>

<tr>
<td>Joost Widgets</td>

<td>Zip</td>

<td>Deflate</td>

<td>.joda (not enforced)</td>

<td><code>application/vnd.joost.joda-archive</code></td>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authoritative information about any
particular widget user agent, please visit the vendor's web site.</small></p>

<h4 class="no-toc no-num" id="interoperable">Interoperable Aspects</h4>

<ul>
<li>Zip format</li>

<li>Deflate compression</li>
</ul>

<h4 class="no-toc no-num" id="fragmentation0">Fragmentation Issues</h4>

<ul>
<li>There is no consistent file extension for widgets; each vendor uses their own unique
file extension.</li>

<li>Nowhere is it defined exactly which parts of the Zip specification should be
supported by a widget user agent. Zip is a large specification that is constantly
evolving. Zip supports multiple compression algorithms and features. If a widget is
packaged using the wrong compression algorithm, it might not be interoperable with
another widget engine or device. Although the issue of compression is not currently a
major issue, it has the potential to become one as widgets become more prevalent on
mobile devices and computers start to work natively in 64-bit.</li>

<li>There is no standardized Media Type, which results in widgets served over HTTP being
associated with only one kind of widget engine. One media type per widget engine results
in vendor lock-in.</li>
</ul>

<h2 id="metadata"><span class="secno">5.</span> Metadata and Configuration</h2>

<p>A widget resource will typically include a configuration document, in which an author
declares metadata and/or some configuration parameters that a widget user agent may use
to configure a widget upon instantiation. All market leading widget engines use XML as
the preferred format for storing metadata.</p>

<dl>
<dt>XML vocabulary</dt>

<dd>The proprietary specification that defines the semantics of the elements and
attributes that authors should use when marking up a configuration document.</dd>

<dt>File name</dt>

<dd>The name of the file as</dd>

<dt>Required?</dt>

<dd>Is the configuration document required for the widget user agent to instantiate the
widget. This was tested by attempting to instantiate a widget without a configuration
document present inside the widget resource.</dd>

<dt>Uses XMLNS</dt>

<dd>Does the configuration document require authors to declare a namespace. Also tested
using a bogus namespace on the root element xmlns=""</dd>

<dt>Conforming Parser?</dt>

<dd>Is the XML parser used by the widget user agent conformant to the XML specification
and XMLNS aware?</dd>
</dl>

<table cellspacing="0" summary="">
<caption>
Configuration documents
</caption>

<thead>
<tr>
<th>Widget User Agent</th>

<th>XML vocabulary</th>

<th>File Name</th>

<th>Required?</th>

<th>Uses XMLNS?</th>

<th>Conforming Parser?</th>
</tr>
</thead>

<tfoot>
<tr>
<th>Widget User Agent</th>

<th>XML vocabulary</th>

<th>File Name</th>

<th>Required?</th>

<th>Uses XMLNS?</th>

<th>&nbsp;</th>
</tr>
</tfoot>

<tbody>
<tr>
<td>Konfabulator</td>

<td>Konfabulator Reference</td>

<td>widget.xml</td>

<td>no</td>

<td>no</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Windows Sidebar</td>

<td>Microsoft Gadgets</td>

<td>gadget.xml</td>

<td>yes</td>

<td>no</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Google Desktop</td>

<td>Google Gadgets</td>

<td>gadget.gmanifest</td>

<td>&nbsp;</td>

<td>no</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Opera Widgets</td>

<td>Opera Spec</td>

<td>config.xml</td>

<td>yes</td>

<td>yes, but not required. If a bogus namespace is given, the widget will not work.</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Apple Dashboard</td>

<td>Apple plist</td>

<td>Info.plist</td>

<td>Yes</td>

<td>no</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Nokia Web-Runtime</td>

<td>Apple plist</td>

<td>Info.plist</td>

<td>Yes</td>

<td>no</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Joost Widgets</td>

<td><cite>Joost Joda</cite></td>

<td>config.xml</td>

<td>yes</td>

<td>yes, but not required (will work with any given namespace).</td>

<td>&nbsp;</td>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authorities information about any particular
widget user agent, please visit the vendor's web site.</small></p>

<h4 class="no-toc no-num" id="interoperable0">Interoperable Aspects</h4>

<ul>
<li>XML is the preferred format for structuring metadata.</li>
</ul>

<h4 class="no-toc no-num" id="fragmentation1">Fragmentation Issues</h4>

<ul>
<li>The XML dialects are all different.</li>

<li>XML parsers are generally non-conforming to the XML and XMLNS specifications.</li>
</ul>

<h3 id="metadata0"><span class="secno">5.1</span> Metadata</h3>

<p>Metadata refers to how authors store information about their widget inside the widget,
and how that data is made accessible to people or machines.</p>

<p>In practice, the inclusion of any metadata elements is generally considered optional
but is nonetheless recommended by vendors. Widget user agents generally make use of
metadata elements in different application contexts such as menus, lists, and
about-boxes. The most common metadata elements captured in configuration documents
include:</p>

<dl>
<dt>Root element:</dt>

<dd>The element found at the root of each configuration document, which contains all
other elements in the document.</dd>

<dt>Name:</dt>

<dd>The human readable name of the widget as it appears in menus or other contexts.</dd>

<dt>Unique identifier:</dt>

<dd>An author assigned unique identifier for the widget.</dd>

<dt>Version identifier:</dt>

<dd>Some string that identifies the version of the widget.</dd>

<dt>Description:</dt>

<dd>A human readable description of the widget, generally describing what it does.</dd>

<dt>Copyright:</dt>

<dd>Copyright information.</dd>

<dt>Authorship:</dt>

<dd>information about the authorship of the widget, including the author's name, email,
and the organization that they may be affiliated with</dd>

<dt>&nbsp;</dt>
</dl>

<table border="0" cellspacing="0" summary="">
<caption>
Metadata elements and their roles
</caption>

<thead>
<tr>
<th>Widget User Agent</th>

<th>Root Element</th>

<th>Name</th>

<th>Unique Identifier</th>

<th>Version Identifier</th>
</tr>
</thead>

<tfoot>
<tr>
<th>Widget User Agent</th>

<th>Root Element</th>

<th>Name</th>

<th>Unique Identifier</th>

<th>Version Identifier</th>
</tr>
</tfoot>

<tbody>
<tr>
<td>Konfabulator</td>

<td>
<p><code>&lt;metadata&gt;</code></p>
</td>

<td><code>&lt;name&gt;text&lt;/name&gt;</code></td>

<td><code>&lt;identifier&gt;<abbr title="universaly unique identifier">UUID</abbr> or
<abbr title="reverse domain format">RD</abbr>&lt;/identifier&gt;</code></td>

<td><code>&lt;version&gt;text&lt;/version&gt;</code></td>
</tr>

<tr>
<td>Windows Vista Sidebar</td>

<td>
<p><code>&lt;gadget&gt;</code></p>
</td>

<td><code>&lt;name&gt;text&lt;/name&gt;</code></td>

<td>Uses <code>&lt;name&gt;</code> and <code>&lt;version&gt;</code>.</td>

<td><code>&lt;version&gt;text(n.n.n.n)&lt;/version&gt;</code></td>
</tr>

<tr>
<td>Google Desktop</td>

<td><code>&lt;gadget&gt;</code></td>

<td><code>&lt;name&gt;text&lt;/name&gt;</code></td>

<td><code>&lt;id&gt;UUID&lt;/id&gt;</code></td>

<td><code>&lt;version&gt;text(n.n.n.n)&lt;/version&gt;</code></td>
</tr>

<tr>
<td>Opera Widgets</td>

<td><code>&lt;widget&gt;</code></td>

<td><code>&lt;widgetname&gt;text&lt;/widgetname&gt;</code></td>

<td><code>&lt;id&gt;&lt;host&gt;URI&lt;/host&gt;
&lt;name&gt;text&lt;/name&gt;&lt;id&gt;</code></td>

<td><code>&lt;id&gt;&lt;revised&gt;W3CDTF&lt;/revised&gt;&lt;/id&gt;</code></td>
</tr>

<tr>
<td>Apple Dashboard</td>

<td><code>&lt;plist version="1.0"&gt;</code></td>

<td><code>&lt;key&gt;CFBundleDisplayName&lt;/key&gt;
&lt;string&gt;text&lt;/string&gt;</code></td>

<td><code>&lt;key&gt;CFBundleIdentifier&lt;/key&gt;<br />
&lt;string&gt;<abbr title="reverse domain format">RD</abbr>&lt;/string&gt;</code></td>

<td>
<code>&lt;key&gt;CFBundleVersion&lt;/key&gt;&lt;string&gt;string&lt;/string&gt;</code></td>
</tr>

<tr>
<td>Nokia Web-Runtime</td>

<td><code>&lt;plist version="1.0"&gt;</code></td>

<td><code>&lt;key&gt;CFBundleDisplayName&lt;/key&gt;
&lt;string&gt;text&lt;/string&gt;</code></td>

<td><code>&lt;key&gt;Identifier&lt;/key&gt;<br />
&lt;string&gt;<abbr title="reverse domain format">RD</abbr>&lt;/string&gt;</code></td>

<td><code>&lt;key&gt;Version&lt;/key&gt;&lt;string&gt;string&lt;/string&gt;</code></td>
</tr>

<tr>
<td>Joost Widgets</td>

<td><code>&lt;widget-manifest&gt;</code></td>

<td><code>&lt;name&gt;text&lt;/name&gt;</code></td>

<td><code>&lt;id&gt;URI&lt;/id&gt;</code></td>

<td>none.</td>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authoritative information about any
particular widget user agent, please visit the vendor's web site.</small></p>

<table cellspacing="0" summary="">
<caption>
Metadata elements and their roles (continued)
</caption>

<thead>
<tr>
<th>Widget User Agent</th>

<th>Description</th>

<th>Authorship</th>

<th>Copyright</th>
</tr>
</thead>

<tfoot>
<tr>
<th>Widget User Agent</th>

<th>Description</th>

<th>Authorship</th>

<th>Copyright</th>
</tr>
</tfoot>

<tbody>
<tr>
<td>Konfabulator</td>

<td><code>&lt;description&gt;Text&lt;/description&gt;</code></td>

<td><code>&lt;author name="" organization="" href=""/&gt;</code></td>

<td><code>&lt;copyright&gt;text&lt;/copyright&gt;</code></td>
</tr>

<tr>
<td>Windows Vista Sidebar</td>

<td><code>&lt;description&gt;Text&lt;/description&gt;</code></td>

<td><code>&lt;author name=""&gt; &lt;info url="URL"/&gt; &lt;logo src="rel-path"/&gt;
&lt;/author&gt;</code></td>

<td><code>&lt;copyright&gt;text&lt;/copyright&gt;</code></td>
</tr>

<tr>
<td>Google Desktop</td>

<td><code>&lt;description&gt;Text&lt;/description&gt;</code></td>

<td><code>&lt;author&gt;text&lt;/author&gt; &lt;authorEmail&gt;text&lt;/authorEmai&gt;
&lt;authorWebsite&gt;URL &lt;/authorWebsite&gt;</code></td>

<td><code>&lt;copyright&gt;text&lt;/copyright&gt;</code></td>
</tr>

<tr>
<td>Opera Widgets</td>

<td><code>&lt;description&gt;Text&lt;/description&gt;</code></td>

<td><code>&lt;author&gt; &lt;name&gt;text&lt;/name&gt; &lt;email&gt;text&lt;/email&gt;
&lt;link&gt;text&lt;/link&gt; &lt;organization&gt;text&lt;/organization&gt;
&lt;/author&gt;</code></td>

<td>none.</td>
</tr>

<tr>
<td>Apple Dashboard</td>

<td>none.</td>

<td>none.</td>

<td>none.</td>
</tr>

<tr>
<td>Nokia Web-Runtime</td>

<td>none.</td>

<td>none.</td>

<td>none.</td>
</tr>

<tr>
<td>Joost Widgets</td>

<td>none.</td>

<td><code>&lt;web site.&gt;URI&lt;/web site.&gt;</code></td>

<td>none. Often included as an xml comment inside the configuration document.</td>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authoritative information about any
particular widget user agent, please visit the vendor's web site.</small></p>

<h4 class="no-toc no-num" id="interoperable1">Interoperable Aspects</h4>

<ul>
<li>Although element names differ, the semantics captured by elements is relatively
consistent.</li>
</ul>

<h4 id="fragmentation"><span class="secno">5.1.1</span> Fragmentation Issues</h4>

<ul>
<li>There some fragmentation in regards to recording the description, authorship
information and copyright.</li>
</ul>

<h3 class="no-toc no-num" id="configuration">Configuration parameters</h3>

<p>The most common configuration parameters include:</p>

<dl>
<dt>Bootstrap:</dt>

<dd>A way to identify the start file (or main content), including a way to identify the
content type of the start file (eg. type="HTML").</dd>

<dd>&nbsp;</dd>

<dt>Network:</dt>

<dd>The need for a widget to access the network.</dd>

<dt>Width and height:</dt>

<dd>The initial rendering dimensions (width, height).</dd>

<dd>&nbsp;</dd>

<dt>Plugins:</dt>

<dd>The intention to use plugins (eg. Flash and Java).</dd>

<dt>Platform:</dt>

<dd>The minimum version of the widget user agent required to run the widget.</dd>
</dl>

<p>Please note that some configuration parameters have a close relationship to the
security model of widgets.</p>

<table cellspacing="0" summary="">
<caption>
Configuration documents
</caption>

<thead>
<tr>
<th>Widget User Agent</th>

<th>Bootstrap</th>

<th>Width and Height</th>

<th>Network</th>

<th>Plugins</th>

<th>Platform</th>
</tr>
</thead>

<tfoot>
<tr>
<th>Widget User Agent</th>

<th>Bootstrap</th>

<th>Width and Height</th>

<th>&nbsp;</th>

<th>&nbsp;</th>

<th>&nbsp;</th>
</tr>
</tfoot>

<tbody>
<tr>
<td>Konfabulator</td>

<td>Not declared. First *.kon file encountered is treated as the start file.</td>

<td>none.</td>

<td><code>&lt;security&gt;<br />
&lt;http name="someSite"&gt;exemple.com&lt;/http&gt;<br />
&lt;/security&gt;</code></td>

<td>none.</td>

<td><code>&lt;platform minVersion="n.n" os="macintosh|windows"/&gt;</code></td>
</tr>

<tr>
<td>Windows Sidebar</td>

<td><code>&lt;host&gt; &lt;base type="HTML" src="rel-path/file" /&gt;
&lt;/host&gt;</code></td>

<td>none.</td>

<td>none. Allowed by default.</td>

<td>none. Allowed by default.</td>

<td><code>&lt;host name="sidebar"&gt; &lt;platform minPlatformVersion ="n.n"
/&gt;&lt;/host&gt;</code></td>
</tr>

<tr>
<td>Google Desktop</td>

<td>Not declared. Root of container must have a "main.xml" file which serves as the start
file.</td>

<td>none.</td>

<td>none. Allowed by default.</td>

<td>none.</td>

<td><code>&lt;gadget minimumGoogleDesktopVersion="n.n.n.n"&gt;<br />
&lt;platform&gt;<br />
&lt;windows minimumGadgetHostVersion="n.n.n.n"/&gt;<br />
&lt;mac minimumGadgetHostVersion="n.n.n.n"/&gt;<br />
&lt;/platform&gt;<br />
&lt;/gadget&gt;</code></td>
</tr>

<tr>
<td>Opera Widgets</td>

<td>None. The start file must be called "index.html" and must be at the root of the
archive.</td>

<td><code>&lt;width&gt;n&lt;/width&gt; &lt;height&gt;n&lt;/height&gt;</code></td>

<td><code>&lt;security&gt; &lt;access&gt;&lt;protocol&gt;http|ftp&lt;/protocol&gt;
&lt;host&gt;IP Address|domain name&lt;/host&gt; &lt;port&gt;integer|integer-range(eg
1200-1500)&lt;/port&gt;&lt;/access&gt; &lt;/security&gt;</code></td>

<td><code>&lt;content&gt;&lt;plugins&gt;yes|no&lt;/plugins&gt;
&lt;java&gt;yes|no&lt;/java&gt;&lt;/content&gt;</code></td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Apple Dashboard</td>

<td><code>&lt;key&gt;MainHTML&lt;/key&gt;
&lt;string&gt;rel-path/any.html&lt;/string&gt;</code></td>

<td>
<p><code>&lt;key&gt;Width&lt;/key&gt; &lt;integer&gt;n&lt;/integer&gt;
&lt;key&gt;Height&lt;/key&gt; &lt;integer&gt;n&lt;/integer&gt;</code></p>

<p>When not present, the width and height of Default.png is used.</p>
</td>

<td>&nbsp;</td>

<td><code>&lt;key&gt;AllowFullAccess&lt;/key&gt; &lt;true|false/&gt;</code></td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Nokia Web-Runtime</td>

<td><code>&lt;key&gt;MainHTML&lt;/key&gt;
&lt;string&gt;rel-path/any.html&lt;/string&gt;</code></td>

<td>&nbsp;</td>

<td><code>&lt;key&gt;AllowNetworkAccess&lt;/key&gt; &lt;true|false/&gt;
&lt;key&gt;AllowFullAccess&lt;/key&gt; &lt;true|false/&gt;</code></td>

<td>none.</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Joost Widgets</td>

<td><code>&lt;main-file&gt;rel-path/a.[jwl,html,svg]&lt;/main-file&gt;</code></td>

<td>&nbsp;</td>

<td><code>&lt;key&gt;AllowNetworkAccess&lt;/key&gt; &lt;true|false/&gt;</code></td>

<td><code>&lt;key&gt;AllowInternetPlugins&lt;/key&gt; &lt;true|false/&gt;</code></td>

<td>&nbsp;</td>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authoritative information about any
particular widget user agent, please visit the vendor's web site.</small></p>

<h4 class="no-toc no-num" id="interoperable2">Interoperable Aspects</h4>

<p class="todo">TBW</p>

<h4 class="no-toc no-num" id="fragmentation2">Fragmentation Issues</h4>

<p class="todo">TBW</p>

<h2 id="authoring"><span class="secno">6.</span> Authoring and Scripting</h2>

<p><dfn id="authoring0">Authoring</dfn> refers to how widgets are created, marked-up and
scripted. In terms of authoring, there is a fairly congruent set of commonalities that
most widget user agents share, and which authors exploit when authoring a widget: mainly
their reliance on Web standards and protocols, and a strong focus on rapid development.
Most widget user agents will typically support <cite><abbr title=
"Hyper Text Transfer Protocol"><a href="#http">HTTP</a></abbr></cite>, <cite><abbr title=
"Internationalized Resource Identifier"><a href="#iri">IRI</a></abbr></cite>s, and
<cite><a href="#unicode">Unicode</a></cite>, as well as <cite><a href=
"#ecmascript">ECMAScript</a></cite>, the <abbr title="Document Object Model">DOM</abbr>,
and the ability to render markup languages, like <abbr title=
"HyperText Markup Language"><cite><a href="#html">HTML</a></cite></abbr> and <abbr title=
"Cascading Style Sheets"><cite><a href="#css">CSS</a></cite></abbr>. Widget user agents
also generally support multimedia resources, such as images, sounds, and some even
video.</p>

<p>To make authoring of widgets possible, widget user agents provide authors with
Application Programming Interfaces (<abbr title=
"application programming interfaces">APIs</abbr>) that are mostly identical to those
found in Web browsers, as well as <abbr title=
"application programming interfaces">APIs</abbr> that provide functionality that is
specific to widgets. Also, because of the rise in popularity of <cite><a href=
"#ajax">Ajax</a></cite>-style development, many widget user agents now implement the
<cite><a href="#xmlhttprequest">XMLHttpRequest</a></cite> object or some similar
mechanism for making asynchronous data requests over <cite><abbr title=
"Hyper Text Transfer Protocol"><a href="#http">HTTP</a></abbr></cite>.</p>

<table border="0" cellspacing="0" summary="">
<caption>
Supported technologies
</caption>

<thead>
<tr>
<th>Widget User Agent</th>

<th>png</th>

<th>gif87</th>

<th>gif89</th>

<th>jpeg</th>

<th>png</th>

<th>svg</th>

<th>mp3</th>

<th>wav</th>

<th>swf</th>

<th>css</th>

<th>js</th>

<th>html4</th>

<th>canvas</th>

<th>XHR</th>
</tr>
</thead>

<tfoot>
<tr>
<th>Widget User Agent</th>

<th>png</th>

<th>gif87</th>

<th>gif89</th>

<th>jpeg</th>

<th>png</th>

<th>svg</th>

<th>mp3</th>

<th>wav</th>

<th>swf</th>

<th>css</th>

<th>js</th>

<th>html4</th>

<th>canvas</th>

<th>XHR</th>
</tr>
</tfoot>

<tbody>
<tr>
<td>Konfabulator</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>no</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>
</tr>

<tr>
<td>Windows Vista Sidebar</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>no</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>no</td>

<td>yes</td>
</tr>

<tr>
<td>Google Desktop</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>no</td>

<td>yes</td>

<td>&nbsp;</td>

<td>no</td>

<td>no</td>

<td>yes</td>

<td>no</td>

<td>no</td>

<td>yes</td>
</tr>

<tr>
<td>Opera Widgets</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>
</tr>

<tr>
<td>Apple Dashboard</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>
</tr>

<tr>
<td>Nokia Web Runtime</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>no</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>no</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>no</td>

<td>yes</td>
</tr>

<tr>
<td>Joost Widgets</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>?</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>

<td>yes</td>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authoritative information about any
particular widget user agent, please visit the vendor's web site.</small></p>

<p class="todo">explain functionality exclusively available to widgets (run programs,
cross domain requests)</p>

<h4 class="no-toc no-num" id="interoperable3">Interoperable Aspects</h4>

<ul>
<li>All widget user agents support XMLHttpRequest.</li>

<li>All but one support HTML and CSS as layout</li>
</ul>

<h4 class="no-toc no-num" id="fragmentation3">Fragmentation Issues</h4>

<ul>
<li>There is some limited fragmantation is regards to support of proprietary
technologies, such as Flash.</li>
</ul>

<h3 id="apis"><span class="secno">6.1</span> APIs</h3>

<p class="todo">TBW</p>

<dl>
<dt>Open page in browser</dt>

<dd>Open a web document in the standard system browser</dd>

<dt>Preferences</dt>

<dd>Get, set and delete user preferences</dd>

<dt>Close widget</dt>

<dd>Destroy instance of currently running widget</dd>
</dl>

<table border="0" cellspacing="0" summary="">
<caption>
Supported technologies
</caption>

<thead>
<tr>
<th>Widget User Agent</th>

<th>Open page in browser</th>

<th>Preferences</th>

<th>Close widget</th>
</tr>
</thead>

<tfoot>
<tr>
<th>Widget User Agent</th>

<th>&nbsp;</th>

<th>&nbsp;</th>

<th>&nbsp;</th>
</tr>
</tfoot>

<tbody>
<tr>
<td>Konfabulator</td>

<td><code>void openURL(url)</code></td>

<td>
<p>&nbsp;</p>
</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Windows Vista Sidebar</td>

<td>no method, use &lt;a href=""&gt; element,<br />
or using javascript within the document: <code>window.open(url)</code></td>

<td><code>System.Gadget.Settings.write(String name, Object Value)<br />
System.Gadget.Settings.writeString(String name, String Value)<br />
System.Gadget.Settings.read(strName)<br />
System.Gadget.Settings.readString(strName)</code></td>

<td><code>System.Gadget.close()</code></td>
</tr>

<tr>
<td>Google Desktop</td>

<td>no method, use &lt;a href=""&gt; element</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Opera Widgets</td>

<td><code>openURL(String url)</code></td>

<td><code>widget.setPreferenceForKey(preference, key)<br />
widget.preferenceForKey(key)<br />
setPreferenceForKey(String preference, null)</code></td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Apple Dashboard</td>

<td><code>openURL(String url)</code></td>

<td><code>widget.setPreferenceForKey(preference, key)<br />
widget.preferenceForKey(key)<br />
setPreferenceForKey(String preference, null)</code></td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Nokia Web Runtime</td>

<td><code>openURL(String url)</code></td>

<td>
<p><code>widget.setPreferenceForKey(preference, key)<br />
widget.preferenceForKey(key)<br /></code> <code>setPreferenceForKey(String preference,
null)</code></p>
</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Joost Widgets</td>

<td><code>navigate(String url);</code></td>

<td>widget.setString(String name, String vlaue);</td>

<td>&nbsp;</td>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authoritative information about any
particular widget user agent, please visit the vendor's web site.</small></p>

<h4 class="no-toc no-num" id="interoperable4">Interoperable Aspects</h4>

<p class="todo">TBW</p>

<h4 class="no-toc no-num" id="fragmentation4">Fragmentation Issues</h4>

<p class="todo">TBW</p>

<h3 id="widget"><span class="secno">6.2</span> Widget object: properties and events</h3>

<h4 class="no-toc" id="properties"><span class="secno">6.2.1</span> Properties of the
Widget object</h4>

<table border="0" cellspacing="0" summary="">
<caption>
Properties of the widget object
</caption>

<thead>
<tr>
<th scope="col">Property</th>

<th scope="col">Konfabulator</th>

<th scope="col">Windows Sidebar</th>

<th scope="col">Google Desktop</th>

<th scope="col">Opera Widgets</th>

<th scope="col">Apple Dashboard</th>

<th scope="col">Nokia Web-Runtime</th>

<th scope="col">Joost Widgets</th>
</tr>
</thead>

<tbody>
<tr>
<td>locale information</td>

<td>locale</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>window.navigator.language</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>window.navigator.language</td>
</tr>

<tr>
<td>Engine version needed to run</td>

<td>requiredEngineVersion</td>

<td>System.Gadget.platformVersion</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>If the widget is visible</td>

<td>visible</td>

<td>System.Gadget.visible</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>The version of the widget as specified in the configuration document</td>

<td>version</td>

<td>System.Gadget.version</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>The name of the widget as specified in the configuration document</td>

<td>name</td>

<td>System.Gadget.name</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td height="25">The details of the author as specified in the configuration document</td>

<td>
<p>widget.author</p>

<p>widget.company</p>
</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>The copyright declaration as in the configuration document</td>

<td>widget.copyright</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Access the unique identifier for the widget</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>
<p><strong>String widget.identifier</strong></p>This read-only property contains a string
value that is unique among all of the instances of a single widget. This value is
assigned by Dashboard and persists between instantiations of each widget instance.
</td>

<td>
<p>string widget.identifier;</p>

<p>&nbsp;</p>
</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>&nbsp;</td>

<td>requiredPlatform</td>

<td>Document, opacity, path, settingsUI, docked, background</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authoritative information about any
particular widget user agent, please visit the vendor's web site.</small></p>

<h4 class="no-toc" id="events"><span class="secno">6.2.2</span> Events</h4>

<p class="todo">TBW</p>

<table border="0" cellspacing="0" summary="">
<caption>
Events of the widget object
</caption>

<thead>
<tr>
<th scope="col">Event</th>

<th scope="col">Konfabulator</th>

<th scope="col">Windows Sidebar</th>

<th scope="col">Google Desktop</th>

<th scope="col">Opera Widgets</th>

<th scope="col">Apple Dashboard</th>

<th scope="col">Nokia Web-Runtime</th>

<th scope="col">Joost Widgets</th>
</tr>
</thead>

<tbody>
<tr>
<td>Widget has loaded</td>

<td>widget.onLoad</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>WUA has focus</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>widget.onshow</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>WUA lost focus</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>widget.onhide</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Widget focus</td>

<td>widget.onGainFocus</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>window.onfocus</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Widget lost focus</td>

<td>widget.onLoseFocus</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>window.onblur</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Widget drag start</td>

<td>widget.onMouseDrag</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>widget.ondragstart</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td height="25">Widget is being dragged</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td height="25">Widget drag end</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>widget.ondragend</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Widget is removed from WUA</td>

<td>widget.onUnload</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>widget.onremove</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Cross widget communication</td>

<td>widget.onTellWidget = function(){ }</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Other</td>

<td>dockOpen onDockClosed onDockOpened onPreferencesChanged onRunCommandInBgComplete
onScreenChanged onTellWidget onWakeFromSleep onWillChangePreferences</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authoritative information about any
particular widget user agent, please visit the vendor's web site.</small></p>

<h4 class="no-toc no-num" id="accessing">Accessing the file system</h4>

<p class="todo">TBW</p>

<p>Execute system level commands or open applications.</p>
<pre>
<code>//If no callbackHandler is present, the command is executed synchronously.
//If callbackHandler is present, command is executed asynchronously. callbackHandler needs to except an argument.
CommandObject widget.system(String command, [Function callbackHandler])

interface CommandObject{
        String property outputString; //the standard out
        String errorString; //any error that was thrown
        String status. //the command's exit status

        // allows handler to receive incremental output (eg ping.)
        EventListener onreadoutput(function handler);
        function cancel(); // cancel the command
        function write(String value); //write a string to standard in
        function close(); //send (EOF) to standard in
}</code>

</pre>
<pre>
<code>
void widget.openApplication(HexNum Uid, String param)

opens an S60 application in stand-alone mode. Values cannot passed back from the opened application to the widget. A widget cannot open another widget using this method.
</code>
</pre>

<h4 class="no-toc no-num" id="interoperable5">Interoperable Aspects</h4>

<p class="todo">TBW</p>

<h4 class="no-toc no-num" id="fragmentation5">Fragmentation Issues</h4>

<p class="todo">TBW</p>

<h2 id="user-interface"><span class="secno">7.</span> User interface and
Accessibility</h2>

<p><dfn id="accessibility">Accessibility</dfn> refers to how end-users, and those with
special needs, can access the content and use the interactive elements of an instantiated
widget. Most market-leading widget user agents allow widgets to be authored using
<cite><a href="#html">HTML</a></cite>, <cite><a href="#css">CSS</a></cite>, and
<cite><a href="#ecmascript">ECMAScript</a></cite>. <cite><a href="#html">HTML</a></cite>,
when authored with care, is generally regarded to be an accessible technology whose
structure and semantics are generally well understood and correctly implemented by most
market-leading widget user agents. To extend It is also therefore theoretically possible
for authors to make their widgets fairly accessible by applying, for example, the
relevant sections of the <em>Web Content Accessibility Guidelines</em> (<cite><a href=
"#wcag"><abbr title="Web Content Accessibility Guidelnes">WCAG</abbr></a></cite>).</p>

<table border="0" cellspacing="0" summary="">
<caption>
Language used to declare the user interface of a widget
</caption>

<thead>
<tr>
<th>Widget User Agent</th>

<th>UI Markup</th>

<th>HTML Renderer</th>
</tr>
</thead>

<tfoot>
<tr>
<th>Widget User Agent</th>

<th><abbr title="User Interface">UI</abbr> Markup</th>

<th>&nbsp;</th>
</tr>
</tfoot>

<tbody>
<tr>
<td>Konfabulator</td>

<td><abbr title="HyperText Markup Language">HTML</abbr> + CSS (through Webkit),
Proprietary <abbr title="Extensible Markup Language">XML</abbr></td>

<td>webkit</td>
</tr>

<tr>
<td>Windows Vista Sidebar</td>

<td><abbr title="HyperText Markup Language">HTML</abbr> + CSS + Proprietary <abbr title=
"Extensible Markup Language">XML</abbr></td>

<td>Internet Explorer</td>
</tr>

<tr>
<td>Google Desktop</td>

<td>Proprietary <abbr title="Extensible Markup Language">XML</abbr></td>

<td>none</td>
</tr>

<tr>
<td>Opera Widgets</td>

<td><abbr title="HyperText Markup Language">(X)HTML</abbr> + <abbr title=
"Cascading Style Sheets">CSS + SVG</abbr></td>

<td>Opera</td>
</tr>

<tr>
<td>Apple Dashboard</td>

<td><abbr title="HyperText Markup Language">HTML</abbr> + <abbr title=
"Cascading Style Sheets">CSS + SVG</abbr></td>

<td>Webkit/safari</td>
</tr>

<tr>
<td>Nokia Web Runtime</td>

<td><abbr title="HyperText Markup Language">HTML</abbr> + <abbr title=
"Cascading Style Sheets">CSS</abbr></td>

<td>Webkit</td>
</tr>

<tr>
<td>Joost Widgets</td>

<td><abbr title="HyperText Markup Language">XHTML</abbr> + CSS + SVG + Proprietary
<abbr title="Extensible Markup Language">XML</abbr></td>

<td>Gecko</td>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authoritative information about any
particular widget user agent, please visit the vendor's web site.</small></p>

<h4 class="no-toc no-num" id="interoperable6">Interoperable Aspects</h4>

<p class="todo">TBW</p>

<h4 class="no-toc no-num" id="fragmentation6">Fragmentation Issues</h4>

<p class="todo">TBW</p>

<h2 id="instantiation"><span class="secno">8.</span> Instantiation</h2>

<p><strong>What addressing mechanism does the widget user agent support at runtime to get
to resources inside the package? (ie. how does a developer address and include things
like images or sounds in their widget?)</strong></p>

<table border="0" cellspacing="0" summary="">
<caption>
The details of configuration document
</caption>

<thead>
<tr>
<th>Widget User Agent</th>

<th>Other expected files</th>
</tr>
</thead>

<tfoot>
<tr>
<th>Widget User Agent</th>

<th>Other expected files</th>
</tr>
</tfoot>

<tbody>
<tr>
<td>Konfabulator</td>

<td>at least one *.kon somewhere in the archive</td>
</tr>

<tr>
<td>Windows Sidebar</td>

<td>at least one html file somewhere in the archive</td>
</tr>

<tr>
<td>Google Desktop</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Opera Widgets</td>

<td>(any folder)* index.html. The folder is selected in alphabetical order, not by the
order in which it appears physically in the archive.</td>
</tr>

<tr>
<td>Apple Dashboard</td>

<td>some [name].html file identified as the start file by the <code>MainHTML</code> key
in the Info.plist file. Icon.png and Default.png. Icon.png is used in the Dashboard bar.
Default.png is shown while the widget loads and used to set the render context of the
widget if width and height keys were not set in Info.plist.</td>
</tr>

<tr>
<td>Nokia Web-Runtime</td>

<td>some [name].html file identified as the start file by the <code>MainHTML</code> key
in the Info.plist file. Icon.png is optional.</td>
</tr>

<tr>
<td>Joost Widgets</td>

<td>&nbsp;</td>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authoritative information about any
particular widget user agent, please visit the vendor's web site.</small></p>

<p class="todo">TBW: discusses different ways that the start file of widget is located:
1. having a preset name (eg. index.html ala Opera Widgets). Having it declared in the
configuration document (ala Joost), Having it match a search pattern (ala
Konfabulator)</p>

<h4 class="no-toc no-num" id="interoperable7">Interoperable Aspects</h4>

<p class="todo">TBW</p>

<h4 class="no-toc no-num" id="fragmentation7">Fragmentation Issues</h4>

<p class="todo">TBW</p>

<h2 id="i18n"><span class="secno">9.</span> Internationalization and Localization</h2>

<p><dfn id="internationalization">internationalization</dfn> refers to the technical
aspects that allow a widget to work in <q>multilingual contexts without requiring an
author to make significant engineering changes to a widget.</q> <dfn id=
"localization">Localization</dfn> is the processes where by a widget is adapted to use
the local conventions of particular end-users (eg. using a particular dialect)<q>.</q> To
allow authors to distribute a widget to multiple locales, the majority of vendors provide
guidelines explain to authors how to make effective use of internationalization
mechanisms built into widget user agents. When authors follow localization guidelines, a
widget user agent can use automated mechanisms to select the appropriate localized
resources for a widget based on a system's locale information; thus making it easier for
authors to create localized widgets.</p>

<p>In the widget space, internationalization is commonly achieved in one of two ways:</p>

<ul>
<li>One way is to have authors place localized resources into specifically named folders
that identify the language and region (eg. "<code>/en-au/</code>" for English Australian)
of localized content. If the widget user agent can identify the end-user's locale, and
the widget package contains matching localized content, then a localized widget will be
presented to the end-user.</li>

<li>Another way is to have authors place localized textual content inside a specifically
named text file, which is in turn placed inside specially named folders (eg.
"<code>/en-au/Localizable.strings</code>"). Inside the text file, localized strings are
identified by an unique identifier and must be formatted using a special syntax. For
instance, Konfabulator uses a special syntax for localizing strings, for example:</li>
</ul>
<pre>
<code>"greeting" = "g'day mate!";</code>
<code>"greeting_gfx" = "/en-au/images/greet.png";</code>
</pre>

<p>Note that this method only localizes textual content, but can be used to also identify
the path or URI to localized resources. At runtime, the widget user agent makes those
localized strings available via a scripting interface:</p>
<pre>

<code>//would set the button's label to "g'day mate!"
myButton.label = widget.getLocalizedString("greeting");</code>

<code>myButton.style.background = widget.getLocalizedString("greeting_gfx");</code>
</pre>

<p>When automated internationalization is not provided by a widget user agent, authors
usually result to using arbitrary solutions to achieve localization. Such is the case for
Opera widgets.</p>

<table border="0" cellspacing="0" summary="">
<caption>
Localization strategies
</caption>

<tbody>
<tr>
<th>Widget User Agent</th>

<th>Localization Strategy</th>

<th>Automatic</th>

<th>Convention followed</th>

<th>Example</th>

<th>Comments</th>
</tr>

<tr>
<td>Konfabulator</td>

<td>Directory-based + <abbr title="JavaScript">JS</abbr></td>

<td>yes</td>

<td>&nbsp;</td>

<td><code>/en-au/Localizable.strings</code></td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Windows Sidebar</td>

<td>Directory-based + <abbr title="JavaScript">JS</abbr></td>

<td>yes</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Google Desktop</td>

<td>Directory-based + <abbr title="JavaScript">JS</abbr></td>

<td>yes</td>

<td>&nbsp;</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Opera Widgets</td>

<td>none</td>

<td>no</td>

<td>none</td>

<td>&nbsp;</td>

<td>Does not support any automated localization strategies.</td>
</tr>

<tr>
<td>Apple Dashboard</td>

<td>Directory-based + <abbr title="JavaScript">JS</abbr></td>

<td>yes</td>

<td>&nbsp;</td>

<td>/en-au/</td>

<td>&nbsp;</td>
</tr>

<tr>
<th>Widget User Agent</th>

<th>Localization Strategy</th>

<th>Automatic</th>

<th>Convention followed</th>

<th>Example</th>

<th>Comments</th>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authoritative information about any
particular widget user agent, please visit the vendor's web site.</small></p>

<h4 class="no-toc no-num" id="interoperable8">Interoperable Aspects</h4>

<p class="todo">TBW</p>

<h4 class="no-toc no-num" id="fragmentation8">Fragmentation Issues</h4>

<p class="todo">TBW</p>

<h2 id="digital"><span class="secno">10.</span> Digital Signatures</h2>

<p>A <dfn id="digital0">digital signature</dfn> is the product of applying a secret
numeric key (known as a <em>private key</em>) and an encryption algorithm over some data
to produce a unique <em>hash value</em>. The only way to validate a digital signature is
to use a corresponding <em>public key</em> in a process known as <em>asymmetric</em>
<em>cryptography</em>.</p>

<p>Although not widely supported by market-leading widget user agents, some widget user
agents allow an author to digitally sign a widget resource. Digitally signing a widget
resource involves calculating the hash values of all the resources inside the widget
resource and encrypting those values using a unique private key that is known only to the
author. The resulting data is bundled inside the widget resource with a digital
certificate, which an author can obtain from a certification authority (such as <a href=
"http://www.verisign.com/">VeriSign</a>) for a charge.</p>

<p>A digital certificate is therefore a trust mechanism intended to verify to a user that
an author really did sign the widget resource. A widget user agent can use the digital
certificate to verify the authenticity and data integrity of the widget resource. In the
rare case where a widget damages the end-user's device, the digital certificate provides
a user with a legal means to prove that a widget resource was signed by a particular
author or publisher.</p>

<p>Because digital certificates can come from untrusted sources, widget user agents will
include <em>root certificates</em> from sources that it trusts. Root certificates are
explicitly trusted and are considered impossible to forge. For example, the Konfabulator
is bundled with the Yahoo! root certificate which it uses to verify widgets signed by
Yahoo! Inc. are in fact signed by Yahoo! Inc.</p>

<table border="0" cellspacing="0" summary="">
<caption>
Digital Signatures
</caption>

<tbody>
<tr>
<th>Widget User Agent</th>

<th>Signature</th>

<th>Certificate Format</th>
</tr>

<tr>
<td>Konfabulator</td>

<td>yes</td>

<td>x509</td>
</tr>

<tr>
<td>Windows Sidebar</td>

<td>yes</td>

<td>x509</td>
</tr>

<tr>
<td>Google Desktop</td>

<td>no</td>

<td>-</td>
</tr>

<tr>
<td>Opera Widgets</td>

<td>no</td>

<td>-</td>
</tr>

<tr>
<td>Apple Dashboard</td>

<td>no</td>

<td>-</td>
</tr>

<tr>
<td>Nokia Web Runtime</td>

<td>Planned</td>

<td>-</td>
</tr>

<tr>
<td>Joost</td>

<td>Planned</td>

<td>-</td>
</tr>

<tr>
<th>Widget User Agent</th>

<th>Signature</th>

<th>Certificate Format</th>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authoritative information about any
particular widget user agent, please visit the vendor's web site.</small></p>

<h4 class="no-toc no-num" id="interoperable9">Interoperable Aspects</h4>

<ul>
<li>The use of X509 certificates.</li>
</ul>

<h4 class="no-toc no-num" id="fragmentation9">Fragmentation Issues</h4>

<ul>
<li>General lack of support for digital signatures.</li>
</ul>

<h2 id="automatic"><span class="secno">11.</span> Automatic Updates</h2>

<p><dfn id="automatic0">Automatic updates</dfn> refers to a service that allows a widget
user agent to automatically check if a new or different version of an installed widget
resource has become available, and somehow acquire the new version and install it.
Automatic updates models work by allowing authors to assign a unique identifier and
version identifier to a widget resource (eg. <code>id="http://example.com/my.wdgt"
version="1.2"</code>).</p>

<p>To keep a widget resource up to date, the widget user agent periodically checks if a
different version of a widget resource has become available on a remote server. In the
case of the Konfabulator, it does this by sending an <cite><a href="#xml"><abbr title=
"eXtensible Markup Language">XML</abbr></a></cite> document that identifies the widget
via an unique identifier, and what version the end-user currently has installed. If a new
version of the widget resource is available on the server, the server sends back an
<cite><a href="#xml"><abbr title="eXtensible Markup Language">XML</abbr></a></cite> file
that contains a URL from where the widget user agent can acquire the latest version. The
widget user agent then informs the end-user that an update to a widget has become
available and if they want to perform the update. If the end-user agrees, then the widget
user agent downloads the latest version of the widget resource, archives the old version,
installs the new one in its place. The updated widget is re-instantiated with its
preexisting preferences (eg. an updated weather forecaster widget will generally not
require the end-user to re-input their preferred city after an update).</p>

<h4 class="no-toc no-num" id="interoperable10">Interoperable Aspects</h4>

<p class="todo">TBW</p>

<h4 class="no-toc no-num" id="fragmentation10">Fragmentation Issues</h4>

<ul>
<li>General lack of support for automatic updates.</li>
</ul>

<h2 id="device"><span class="secno">12.</span> Device Independence</h2>

<p class="todo">Need to read up on how Nokia Web Runtime recommends authors deal with
migration of Dashboard widgets, etc.</p>

<h4 class="no-toc no-num" id="interoperable11">Interoperable Aspects</h4>

<p class="todo">TBW</p>

<h4 class="no-toc no-num" id="fragmentation11">Fragmentation Issues</h4>

<p class="todo">TBW</p>

<h2 id="security"><span class="secno">13.</span> Security Models</h2>

<p><dfn id="security0">Security model</dfn> refers to the security policies under which a
widget user agent operates that either prevents or allows an instantiated widget from
performing particular actions (eg. accessing the network or reading/writing files). When
compared to Web browsers, some market-leading widget user agents have a comparatively
relaxed security model that allows an instantiated widget to read, write, modify, and/or
delete files, automatically upload files, automatically download files, execute local
applications, and even perform cross-domain request to "mash-up" data from multiple
different sources. All without the end-user having any indication that their privacy and
security might be at risk.</p>

<p>The ability to perform most of the aforementioned actions is strictly forbidden in
documents running in Web Browsers. Such a relaxed security model has been generally
positive in the widget space with very useful and powerful widgets being developed.
However, this has created an environment where users are left extremely vulnerable to
malicious attacks, and serious security risks have been demonstrated. Some market-leading
widget user agents, such as Opera Widgets, have a much tighter security model that
adheres more closely to the security model of a Web Browser; as such, they may be less
prone to serious security issues.</p>

<p class="todo">Need to discuss how security declarations are made using pInfo list or
Opera's security element.</p>

<h4 class="no-toc no-num" id="interoperable12">Interoperable Aspects</h4>

<p class="todo">TBW</p>

<h4 class="no-toc no-num" id="fragmentation12">Fragmentation Issues</h4>

<p class="todo">TBW</p>

<h2 id="icons"><span class="secno">14.</span> Icons</h2>

<table border="0" cellspacing="0" summary="">
<caption>
Icons
</caption>

<thead>
<tr>
<th>Widget User Agent</th>

<th>Element in configuration file</th>

<th>Supported Types</th>

<th>Preferred</th>

<th>Comments</th>
</tr>
</thead>

<tfoot>
<tr>
<th>Widget User Agent</th>

<th>Element</th>

<th>Supported Types</th>

<th>&nbsp;</th>

<th>Comments</th>
</tr>
</tfoot>

<tbody>
<tr>
<td>Konfabulator</td>

<td><code>&lt;image usage="dock|security" src="images/some.png"/&gt;</code></td>

<td>GIF, PNG.</td>

<td>&nbsp;</td>

<td>
<p>Two images may be declared, depending on the <code>usage</code> attribute. The
<code>usage</code> attribute allows either values <code>dock</code>|<code>security</code>
to indicate where the image should be used. Security image is shown as part of the widget
security warning when the widget is instantiated.</p>
</td>
</tr>

<tr>
<td>Windows Vista Sidebar</td>

<td>
<p>&lt;icons&gt; &lt;icon src="rel-path" [width="" height=""]&gt; &lt;/icons&gt;</p>

<p>&lt;hosts&gt; &lt;host&gt; &lt;defaultImage src=""/&gt; &lt;/host&gt;</p>
</td>

<td>any GDI+ 1.0 supported format.</td>

<td>&nbsp;</td>

<td>
<p>Having multiple icon elements allows the engine to select the icon most appropriate
for communication based on size. Preferred size is 64px*64px, but any size is ok.</p>

<p class="todo">The documentation contradicts itself in regards to icon and defaultImage.
Need to verify which one is actually used!</p>
</td>
</tr>

<tr>
<td>Google Desktop</td>

<td>
<p>&lt;small-icon&gt;rel-path/some.png&lt;small-icon&gt;</p>

<p>&lt;icon&gt;rel-path/some.png&lt;small-icon&gt;</p>
</td>

<td>PNG</td>

<td>PNG</td>

<td>
<p class="todo">Need to test other formats</p>
</td>
</tr>

<tr>
<td>Opera Widgets</td>

<td>
<p>&lt;icon&gt;relative-path/some.png&lt;/icon&gt;</p>

<p>&nbsp;</p>
</td>

<td>GIF, PNG.</td>

<td>&nbsp;</td>

<td>&nbsp;</td>
</tr>

<tr>
<td>Apple Dashboard</td>

<td>none.</td>

<td>PNG</td>

<td>&nbsp;</td>

<td>
<p>Not declared. An optional icon must appear in the root of the archive and must be
called icon.png. If the icon is missing, then the runtime will use a default icon.</p>
</td>
</tr>

<tr>
<td>Nokia Web-Runtime</td>

<td>none.</td>

<td>PNG</td>

<td>PNG</td>

<td>include an "icon.png" file at the root of the widget.</td>
</tr>

<tr>
<td>Joost Widgets</td>

<td>
<p>&lt;icon&gt;relative-path/some.svg&lt;/icon&gt;</p>

<p>&nbsp;</p>
</td>

<td>SVG, PNG, JPEG, GIF</td>

<td>&nbsp;</td>

<td>SVG or PNG are preferred.</td>
</tr>
</tbody>
</table>

<p class="disclaimer"><small>*Although care has been take to ensure the accuracy of the
information contained in this table, there is no guarantee that the information is
complete, correct, or up-to-date. To obtain authoritative information about any
particular widget user agent, please visit the vendor's web site.</small></p>

<p class="todo">This section will describe how icons are used by different widget
engines. It will discuss static icons (images, pngs), and dynamic icons, such as Yahoo!'s
icons. Might also talk briefly about iPod/Phone icons here too, as they are dynamic.</p>

<h4 class="no-toc no-num" id="interoperable13">Interoperable Aspects</h4>

<p>PNG, GIF87/89</p>

<p class="todo">TBW</p>

<h4 class="no-toc no-num" id="fragmentation13">Fragmentation Issues</h4>

<p class="todo">TBW</p>

<h2 id="standardizable"><span class="secno">15.</span> Standardizable Aspects of
Widgets</h2>

<p>The following list represents the aspects of a widget that members of the working
group have identified as requiring standardization to reduce fragmentation in the widget
space. Aspects that are currently outside the scope of the working group charter are
proceeded by the text "<strong><dfn id="out-of">out of scope</dfn></strong>". To address
aspects beyond the scope of the working group, the working group will require liaison
with other working groups at the <abbr title="World Wide Web Consortium"><a href=
"http://w3.org">W3C</a></abbr> and possibly other related consortia such as the
<abbr title="Open Mobile Alliance">OMA</abbr> and the <abbr title=
"Open Ajax Alliance">OAA</abbr>.</p>

<p><dfn id="standardizable0">Standardizable aspects of widgets</dfn> include:</p>

<ul>
<li>Finding a suitable packaging format capable of encapsulating and structuring
resources for distribution and deployment, including:

<ul>
<li>The relevant technical aspects of the physical packaging format that make the format
interoperable across multiple platforms and mobile devices.</li>

<li>The abstract container, including required parts and hierarchies (eg. required files
and folders, if any).</li>

<li>The model by which the internal structure of a widget resource can be exploited by an
instantiated widget for localization purposes in internationalized contexts.</li>

<li>A means for an instantiated widget to address resources in a widget resource at
runtime.</li>

<li>A file extension.</li>

<li>A MIME type to formally denote that a widget resource distributed over <cite><a href=
"#http"><abbr title="Hyper Text Transfer Protocol">HTTP</abbr></a></cite> conforms to the
Widgets 1.0: Packaging specification.</li>

<li>A widely supported digital signature format that adequately provides data security,
authenticity and non-repudiation.</li>
</ul>
</li>

<li>The configuration document language including:

<ul>
<li>The structure, semantics, and processing model for a vocabulary that would make up
the configuration document format.</li>

<li>Metadata elements pertaining to authorship (eg. author's name, email, etc).</li>

<li>Metadata elements pertaining to the widget (eg. id, title, description, etc).</li>

<li>Configuration parameters (eg. width, height, network access, etc).</li>

<li>A bootstrap mechanism that allows the widget user agent to find the start file of a
widget resource.</li>

<li>A model for finding a start file of a widget resource when a bootstrap is unavailable
or is in error.</li>

<li>A means for distinguishing the configuration document from other resources.</li>

<li>A means to declare an alternative representation of a widget (eg. an image icon) for
when a widget has not been instantiated.</li>
</ul>
</li>

<li>A widgets API that could be implemented by a widget user agent and made available to
an instantiated widget that would allow authors to:

<ul>
<li>Access preferences particular to each instantiated widget.</li>

<li>Access runtime configuration properties and other relevant platform properties
(<strong><a href="#out-of">out of scope</a></strong>).</li>

<li>Access to services particular to the device on which the widget has been instantiated
(eg. camera, short message service, address book, etc) (<strong><a href="#out-of">out of
scope</a></strong>).</li>

<li>The ability to instantiate other applications on an end-user's device
(<strong><a href="#out-of">out of scope</a></strong>).</li>

<li>Access metadata values that the author declared in the configuration document.</li>

<li>Capture events and access properties that are particular to each instantiated
widget.</li>

<li>Control alternative runtime representations of a widget (eg. the docked
representation).</li>
</ul>
</li>

<li>The security model/policies that determines what an instantiated widget can access
while running on a end-user's device.</li>

<li>A pre-existing language to declare the user interface in an accessible manner (eg.
mandating the use of <abbr title="HyperText Markup Language"><cite><a href=
"#html">HTML</a></cite></abbr> or some other <cite><a href="#xml"><abbr title=
"eXtensible Markup Language">XML</abbr></a></cite> vocabulary).</li>

<li>A <cite><a href="#http"><abbr title=
"Hyper Text Transfer Protocol">HTTP</abbr></a></cite>-based model for a widget user agent
to check if an updated version of a widget resource has become available for
download.</li>
</ul>

<p><dfn id="standardizable1">Standardizable aspects of widget engines</dfn> include:</p>

<ul>
<li>
<p class="todo">TBW</p>
</li>
</ul>

<h2 class="no-num" id="acknowledgments">Acknowledgments</h2>

<p>The editor would particularly like to thank Corin Edwards for his help on improving
the design on of <a href="#figure">figure 1</a>.</p>

<p>The editor would like to thank to the following people who have contributed to this
document (ordered by first name):</p>

<ul>
<li>Alexander Dreiling</li>

<li>Anne van Kesteren</li>

<li>Arthur Barstow</li>

<li>Arun Ranganathan</li>

<li>Benoit Suzanne</li>

<li>Bert Bos</li>

<li>Bradford Lassey</li>

<li>Cameron McCormack</li>

<li>Cliff Schmidt</li>

<li>Claudio</li>

<li>Coach Wei</li>

<li>Corin Edwards</li>

<li>Dan Brickley</li>

<li><span>David Pollington</span></li>

<li>Dean Jackson</li>

<li>Debra Polson</li>

<li>Doug Schepers</li>

<li>Ed Voas</li>

<li>Gene Vayngrib</li>

<li>Guido Grassel</li>

<li>Jay Sweeney</li>

<li>Jim Ley</li>

<li>Jose Manuel Cantera Fonseca</li>

<li>Kevin Lawver</li>

<li>Krzysztof Maczy&#324;ski</li>

<li>Lachlan Hunt</li>

<li>Marc Silbey</li>

<li>Mark Baker</li>

<li>Mikko Pohja</li>

<li>Philipp Heltewig</li>

<li>Stephen Paul Weber</li>

<li>Thomas Landspurg</li>

<li>Yang Wong</li>

<li>Zachary Fitz-Walter</li>
</ul>

<h2 class="no-num" id="references">References</h2>

<dl class="references">
<dt><dfn id="ajax">Ajax</dfn></dt>

<dd><a href="http://www.adaptivepath.com/publications/essays/archives/000385.php">Ajax: A
New Approach to Web Applications</a>. J. J. Garrett. February 18, 2005. Adaptive Path.
Available at <a href=
"http://www.adaptivepath.com/publications/essays/archives/000385.php">http://www.adaptivepath.com/publications/essays/archives/000385.php</a></dd>

<dt><dfn id="apple">Apple pList</dfn></dt>

<dd><a href=
"http://developer.apple.com/documentation/CoreFoundation/Conceptual/CFPropertyLists/index.html">
Introduction to Property List Programming Topics for Core Foundation</a>, Apple Computer
Inc, 7 February 2006. Available at <a href=
"http://developer.apple.com/documentation/CoreFoundation/Conceptual/CFPropertyLists/index.html">
http://developer.apple.com/documentation/CoreFoundation/Conceptual/CFPropertyLists/index.html</a></dd>

<dt><dfn id="css">CSS</dfn></dt>

<dd><a href="http://www.w3.org/TR/CSS21/">Cascading Style Sheets, level 2, revision
1</a>, B. Bos, T. &Ccedil;elik, I. Hickson, and H. Wium Lie. W3C Candidate Recommendation
19 July 2007. Available at <a href=
"http://www.w3.org/TR/CSS21/">http://www.w3.org/TR/CSS21</a></dd>

<dt><dfn id="dom">DOM</dfn></dt>

<dd><a href="http://www.w3.org/TR/REC-DOM-Level-1/">Document Object Model (DOM) Level 1
Specification</a>, L. Wood et al., 1 October 1998. Available at <a href=
"http://www.w3.org/TR/REC-DOM-Level-1/">http://www.w3.org/TR/REC-DOM-Level-1</a></dd>

<dt><dfn id="dashboard0">Dashboard Reference</dfn></dt>

<dd><a href=
"http://developer.apple.com/documentation/AppleApplications/Reference/Dashboard_Ref/index.html">
Dashboard Reference</a>, Apple Computer, Inc, May 2006. Available at <a href=
"http://developer.apple.com/documentation/AppleApplications/Reference/Dashboard_Ref/index.html">
http://developer.apple.com/documentation/AppleApplications/Reference/Dashboard_Ref/index.html</a></dd>

<dt><dfn id="google0">Google Gadgets</dfn></dt>

<dd><a href="http://desktop.google.com/script.html">Google Desktop Sidebar Scripting
<abbr title="Application Programming Interface">API</abbr></a>, Google Inc., 2006.
Available at <a href=
"http://desktop.google.com/script.html">http://desktop.google.com/script.html</a></dd>

<dt><dfn id="json">JSON</dfn></dt>

<dd><a href="http://www.ietf.org/rfc/rfc4627.txt">The application/json media type for
ECMAScript Object Notation</a>. D. Crockford. July 2006. Available at <a href=
"http://www.ietf.org/rfc/rfc4627.txt">http://www.ietf.org/rfc/rfc4627.txt</a></dd>

<dt>&nbsp;</dt>

<dt><dfn id="opera0">Opera Spec</dfn></dt>

<dd><a href=
"http://oxine.opera.com/widgets/documentation/widget-configuration.html">Opera Widgets
Specification 1.0</a>, A. Bersvendsen (Editor), Opera Software, 30 Apr, 2007. Available
at <a href=
"http://oxine.opera.com/widgets/documentation/widget-configuration.html">http://oxine.opera.com/widgets/documentation/widget-configuration.html</a></dd>

<dt><dfn id="sidebar">Sidebar Reference</dfn></dt>

<dd><a href="http://windowssdk.msdn.microsoft.com/en-us/library/ms722795.aspx">Windows
Sidebar Reference</a>, Microsoft Corporation, 2006. Available at <a href=
"http://msdn2.microsoft.com/en-us/library/aa965853.aspx">http://msdn2.microsoft.com/en-us/library/aa965853.aspx</a></dd>

<dt><dfn id="xml-internationalization">XML Internationalization and
Localization</dfn></dt>

<dd><a class="booktitle" href="#xml-internationalization">XML Internationalization and
Localization</a>. Savourel, Y. Sams Publishing, Indiana. June 2001.</dd>

<dt><dfn id="konfabulator0">Konfabulator Reference</dfn></dt>

<dd><a href=
"http://widgets.yahoo.com/gallery/dl_item.php?item=WidgetEngineReference_3.1.1.pdf">Konfabulator
Reference 4.5 Reference Manual</a> Yahoo! Inc., April 14, 2006. Available at <a href=
"http://widgets.yahoo.com/gallery/dl_item.php?item=WidgetEngineReference_3.1.1.pdf">http://Widgets.yahoo.com/gallery/dl_item.php?item=WidgetEngineReference_3.1.1.pdf</a></dd>

<dt><dfn id="wcag">WCAG</dfn></dt>

<dd><a href="http://www.w3.org/TR/WAI-WEBCONTENT/">Web Content Accessibility Guidelines
1.0</a>. W. Chisholm, G. Vanderheiden, and I. Jacobs. W3C Recommendation, 5 May 1999.
Available at <a href=
"http://www.w3.org/TR/WAI-WEBCONTENT/">http://www.w3.org/TR/WAI-WEBCONTENT/</a></dd>

<dt><dfn id="ecmascript">ECMAScript</dfn></dt>

<dd><a href=
"http://www.ecma-international.org/publications/standards/Ecma-262.htm">ECMAScript
Language Specification</a>, Third Edition. <abbr title=
"European Computer Manufacturers Association">ECMA</abbr>, December 1999. Available at
<a href=
"http://www.ecma-international.org/publications/standards/Ecma-262.htm">http://www.ecma-international.org/publications/standards/Ecma-262.htm</a></dd>

<dt><dfn id="html">HTML</dfn></dt>

<dd><a href="http://www.w3.org/TR/html401/">HTML 4.01 Specification</a>, D. Raggett, A.
Le Hors, I. Jacobs, 24 December 1999. Available at <a href=
"http://www.w3.org/TR/html401/">http://www.w3.org/TR/html401/</a></dd>

<dt><dfn id="http">HTTP</dfn></dt>

<dd><a href="http://www.ietf.org/rfc/rfc2616.txt">Hypertext Transfer Protocol --
HTTP/1.1</a>, R. Fielding, J. Gettys, J. Mogul, H. Frystyk Nielsen, L. Masinter, P. Leach
and T. Berners-Lee, June 1999. Available at <a href=
"http://www.ietf.org/rfc/rfc2616.txt">http://www.ietf.org/rfc/rfc2616.txt</a></dd>

<dt><dfn id="mime-type">MIME Type</dfn></dt>

<dd><a href="http://www.ietf.org/rfc/rfc2046.txt">Multipurpose Internet Mail Extensions
(MIME) Part Two: media types</a>, N. Freed and N. Borenstein, November 1996. Available at
<a href=
"http://www.ietf.org/rfc/rfc2046.txt">http://www.ietf.org/rfc/rfc2046.txt</a>.</dd>

<dt><dfn id="unicode">Unicode</dfn></dt>

<dd><em>The Unicode Standard</em>, The Unicode Consortium, Version 5.</dd>

<dt><dfn id="xml">XML</dfn></dt>

<dd><a href="http://www.w3.org/TR/2000/REC-xml-20001006">Extensible Markup Language (XML)
1.0 Specification (Second Edition)</a>, T. Bray, J. Paoli, C. M. Sperberg-McQueen, E.
Maler, 6 October 2000. Available at <a href=
"http://www.w3.org/TR/REC-xml/">http://www.w3.org/TR/REC-xml/</a></dd>

<dt><dfn id="xmlhttprequest">XMLHttpRequest</dfn></dt>

<dd><a href="http://www.w3.org/TR/XMLHttpRequest/">The XMLHttpRequest object</a>. A. van
Kesteren. 2006. W3C Working Draft, Available at <a href=
"http://www.w3.org/TR/XMLHttpRequest/">http://www.w3.org/TR/XMLHttpRequest/</a></dd>

<dt><dfn id="x.509">X.509</dfn></dt>

<dd>CCITT, <em>Recommendation X.509: The Directory Authentication Framework</em>,
1988.</dd>

<dt><dfn id="iri">IRI</dfn></dt>

<dd><a href="http://www.ietf.org/rfc/rfc3987">Internationalized resource Identifiers
(IRIs)</a>, M. Duerst, M. Suignard. IETF, January 2005. RFC3987 is Available at <a href=
"http://www.ietf.org/rfc/rfc3987">http://www.ietf.org/rfc/rfc3987</a></dd>

<dt><dfn id="zip">Zip</dfn></dt>

<dd><a href="http://www.pkware.com/documents/casestudies/APPNOTE.TXT">.ZIP File Format
Specification</a>. PKWare Inc., September 2007. Available at <a href=
"http://www.pkware.com/documents/casestudies/APPNOTE.TXT">http://www.pkware.com/documents/casestudies/APPNOTE.TXT</a></dd>
</dl>

<h3 class="no-num" id="related">Related Sources</h3>

<dl class="references">
<dt>&nbsp;</dt>

<dt><dfn id="light">Light Web Applications</dfn></dt>

<dd><a href="http://www.w3.org/People/Bos/webapps.html">Setting the scope for
light-weight Web-based applications</a>. B. Bos. Work in Progress. 26 Feb 2004. Available
at <a href=
"http://www.w3.org/People/Bos/Webapps.html">http://www.w3.org/People/Bos/Webapps.html</a></dd>

<dt><dfn id="xml-packaging">XML Packaging</dfn></dt>

<dd><a href="http://www.w3.org/XML/2000/07/xml-packaging-charter.html"><abbr title=
"Extensible Markup Language">XML</abbr> Packaging Working Group Charter</a>, J. Nava.
W3C. Available at <a href=
"http://www.w3.org/XML/2000/07/xml-packaging-charter.html">http://www.w3.org/XML/2000/07/xml-packaging-charter.html</a></dd>

<dt><dfn id="semantic">Semantic Webapps</dfn></dt>

<dd><a href=
"http://www.w3.org/2001/sw/Europe/talks/200409-svgopen/slide1-0.html">Semantic Webapps?
Lightweight RDF interfaces for SVG</a>. Sept 7, SVGOpen 2004, Japan. Available from:
<a href=
"http://www.w3.org/2001/sw/Europe/talks/200409-svgopen/slide1-0.html">http://www.w3.org/2001/sw/Europe/talks/200409-svgopen/slide1-0.html</a></dd>
</dl>
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