The Composite Application Framework library dynamically loads script files on demand. With the Library.register(id, url) method, you can register a named group of script files to load later. The Library.load(id, onload) method loads the named group or directly-specified group of script files, and then executes the specified callback method when loading is completed. For example, the scripts needed to execute Scriptaculous Effects are pre-registered as the scriptaculous/effects group. To execute a scriptaculous effect, you must call Library.load() to load the scriptaculous effect library, pass a method to execute once the library has finished loading. For example:

Instead of using a registered group name, you also can pass Library.load() the URL of a script to load directly. You can specify multiple URLs or named groups as a space-separated string, for example http://example.com/foo.js http://example.com/bar.js.