Good style for web applications requires that Javascript and CSS for web pages are kept separate to the HTML they enhance. Confluence itself is moving towards this model, and the tools that Confluence uses to do this are also available to plugin developers.

This functionality is only available in Confluence 2.8 and later.

If you are developing a theme plugin and would like to include css resources, see Theme Stylesheets instead.

Including a custom Javascript or CSS file from a plugin

In your atlassian-plugin.xml, you should add a new web resource module in this format:

<atlassian-plugin key="com.example.confluence.plugin.special" name="My Special Plugin" i18n-name-key="com.example.confluence.plugin.name">
    <!-- ... -->

    <web-resource key="mechanical-parts" name="Mechanical Parts" i18n-name-key="com.example.confluence.plugin.special.mechanical.parts.name">
        <resource type="download" name="widgets.js" location="js/widgets.js"/>
        <resource type="download" name="sprockets.css" location="styles/sprockets.css"/>
    </web-resource>

    <!-- ... -->
</atlassian-plugin>

For each resource, the location of the resource should match the path to the resource in your plugin JAR file. For example, 'widgets.js' in the above plugin JAR would be at js/widgets.js. Resource paths are namespaced to your plugin, so they can't conflict with resources in other plugins with the same location (unlike say i18n or Velocity resources). However, you may find it convenient to use a path name which is specific to your plugin to be consistent with these other types.

Then, in a Velocity template that requires that Javascript file, you use the #requireResource macro, with the plugin key followed by a colon and the key of the web-resource:

#requireResource("com.example.confluence.plugin.special:mechanical-parts")

In the HTML header of any page containing that Velocity template, all resources included in the web-resource plugin will be written out as script or link tags to include the relevant resource:

<html>
<head>
    <!-- ... -->
    <script type="text/javascript" src="/s/.../_/download/com.example.confluence.plugin.special:mechanical-parts/widgets.js"></script>
    <link type="text/css" rel="stylesheet" src="/s/.../_/download/com.example.confluence.plugin.special:mechanical-parts/spockets.css">
    <!-- ... -->
</head>

<!-- ... -->

</html>

Only one instance of each script or stylesheet will be included, and they will appear in the order they are requested in the Velocity rendering process.

The Javascript and CSS resources will be served with an expires header that means the browser will cache these resources forever. When you change these resources in your plugin, you will need to increment the version number of your plugin. This changes the URL generated above – one of the numbers between /s/ and /_/ is your plugin version – and results in the browser pulling down the updated resource.

The rich text editor and preview views do not currently use dynamic stylesheets provided by a macro rendered in this way.

Web resource configuration

As well as declaring a resource in your plugin, you can declare the media type (for CSS resources) and whether the resource should be wrapped in an Internet Explorer conditional comment.

For example, requesting this resource will insert a <link> in the header with a media value of "print":

<web-resource key="mechanical-parts" name="Mechanical Parts"
    i18n-name-key="com.example.confluence.plugin.special.mechanical.parts.name">
    <resource type="download" name="sprockets.css" location="styles/sprockets.css">
        <param name="media" value="print"/>
    </resource>
</web-resource>

The web resource declaration below says that the resource should be wrapped in an Internet Explorer conditional comment, which means it will only be used by Internet Explorer. This is useful for IE-specific styling to work around browser bugs.

<web-resource key="mechanical-parts" name="Mechanical Parts" 
    i18n-name-key="com.example.confluence.plugin.special.mechanical.parts.name">
    <resource type="download" name="sprockets-ie.css" location="styles/sprockets.css">
        <param name="ieonly" value="true"/>
    </resource>
</web-resource>

The HTML output when this resource is included will be something like this:

<!--[if IE]>
<link type="text/css" rel="stylesheet" media="all"
    href="/s/1418/13/1.0/_/download/resources/plugin.example:mechanical-parts/sprocket-ie.css" />
<![endif]-->

The ieonly parameter also works for JavaScript resources.

You can also provide a parameter with name title, which will be the title attribute of the CSS <link> tag.

Including a Javascript library provided by Confluence

Confluence currently includes several Javascript libraries which can be used by plugins. The versions of these libraries are subject to change, but only across major versions of Confluence.

In the Confluence source code, these libraries are included in a plugin XML file called web-resources.xml.

Library

Web resource key

Current version

Details

Scriptaculous

confluence.web.resources:scriptaculous

1.5rc3

Includes effects, dragdrop, controls and util.

Prototype

confluence.web.resources:prototype

1.4.0_pre11

Version found in the scriptaculous lib directory. Also includes a domready extension, see domready.js.

jQuery

confluence.web.resources:jquery

1.2.3

For compatibility with prototype, you must use 'jQuery()' not '$' to access jQuery.

DWR

confluence.web.resources:dwr

1.1.4

Includes engine and util.

To include one of these libraries in all pages in which your Velocity template appear, simply use the #requireResource macro as above. For example, if your macro requires jQuery, add the following to its Velocity template:

#requireResource("confluence.web.resources:jquery")

Note: Use of Scriptaculous and Prototype is deprecated as of Confluence 2.9. Use of these libraries in Confluence core will be gradually replaced with jQuery over the next few releases. Plugin developers should start doing the same with their front-end code, because both Prototype and Scriptaculous will be removed from a future release of Confluence.

Running scripts when the page loads

The recommended way to load scripts when the page is ready, known as 'on-DOM-ready', is to use the Atlassian Javascript (AJS) abstraction. This avoid depending on a particular Javascript library which may not remain in Confluence.

AJS.toInit(function () {
    // ... your initialisation code here
});

This has the additional benefit of ensuring any functions or variables you declare here are not in the global scope, which is important for best interoperability with other plugins in Confluence.

Achieving progressive enhancement

We recommend you separate your markup, styles and Javascript when developing a Confluence plugin, according to the design principles of progressive enhancement. To assist with this, there are a few hooks in AJS and in Confluence in general to make this easier.

Dynamic content in Javascript

If you need to pass information from Velocity to Javascript, like for localised text, you can use AJS.params. This automatically looks up values inside fieldsets marked with a class of "parameters" inside your markup. For example, given the following markup:

<fieldset class="parameters hidden">
    <input type="hidden" id="deleteCommentConfirmMessage" value="$action.getText('remove.comment.confirmation.message')">
</fieldset>

You can have your Javascript access the localised text without embedding it by using AJS.params:

if (confirm(AJS.params.deleteCommentConfirmMessage)) {
    // ...
}

Getting the context path

Usually, you can use relative paths in stylesheets and Javascript to avoid the need for knowing the context path. However, Confluence makes this available through a meta tag in the header which looks like this:

<meta id="confluence-context-path" name="confluence-context-path" content="/confluence">

With jQuery, or even normal Javascript, it is quite easy to retrieve this for use in scripts:

// normal JS
document.getElementById("confluence-context-path").content

// jQuery
$("#confluence-context-path").attr("content")

More information

Couldn't you do this already? What's changed in Confluence 2.8?

Since Confluence 2.6, you've been able to use #includeJavascript, which puts the script tag inline, exactly where that Velocity macro appears. You've also always been able to include inline scripts or styles in your macros. However, there are a couple of problems with this that we've solved in 2.8:

  1. The Javascript might override other script already present in the page, including scripts used by Confluence.
  2. Inline Javascript or styles might appear multiple times in the page, wasting bandwidth and potentially causing conflicts.

Many plugin authors found that including Javascript in their plugins meant the plugin broke in some places, such as in the preview window, if two copies of the macro were on the same page.

By using the new #requireResource, you're guaranteed to only get one instance of the script appearing on a page, and it will be cached by browsers until your plugin is upgraded.

Do I have to use Velocity to request these resources? What about in Java?

You can achieve the same result in Java via the WebResourceManager. Use the same method as described above for Velocity: webResourceManager.requireResource(String). The WebResourceManager is a bean you can get injected by Spring. Do this within the scope of the request.

In most cases, using Velocity makes more sense, because the declaration of the JS and CSS should be close to the code which uses it.

RELATED TOPICS

Confluence Plugin Guide
Writing Confluence Plugins

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