The YUI SWF Utility provides a standardized method for embedding the Adobe Flash player in web pages. Specifically, the SWF Utility:

  1. Creates browser-specific, standards-compliant markup for correctly embedding an instance of Flash player plugin (in browsers with Netscape Plugin Architecture), or an instance of Flash Player ActiveX control (in Internet Explorer).
  2. Allows developers to set a requirement for the minimum version of Flash player installed on the end user's computer.
  3. Provides a convenient single method instantiation of the embedded player properties and variables.
  4. Wraps the ExternalInterface API of the Flash player to allow method calls on specific player instances.
  5. In conjunction with the YUIBridge ActionScript API, allows Flash applications to dispatch events that get converted to native YUI events.
NOTE: Due to security issues, as of 3.13.0:

Important usage notes:

{{>getting-started}}

Using the SWF Utility

This section describes how to use the SWF Utility in further detail.

Anatomy of the SWF Utility

The SWF Utility uses the browser information from the `Y.ua` variable to generate the appropriate markup for embedding the Flash player. The markup that the SWF Utility generates is entirely based on the `` tag, and therefore will not work in older browsers that use the non-standard `` tag.

In addition, the SWF Utility also determines the version of the Flash player (using YUI's `swfdetect` library), and places that information in `Y.ua.flash` as a period-delimited string (MajorVersion.MinorVersion.Revision). This information is used by SWF utility to prevent Flash Player embedding if the version of user's installed Flash player does not match that required by the developer.

While the SWF Utility provides a direct access to the instance of the Flash player it encapsulates, it is recommended that all communication to that instance occur via the methods provided by the SWF Utility (see below.)

Configuring and Instantiating the SWF Utility

For simplicity, all configuration of the embedded Flash player instance happens in the SWF Utility at construction time, and therefore, all configuration parameters must be provided as arguments to the SWF constructor.

By default, the SWF constructor requires only two arguments – the reference to the container in which the instance of the Flash player should be placed, and the URL of the swf application that the Flash player instance should load. Note that the Flash player instance created by the SWF Utility always adopts the size of the parent container it is placed into; therefore, setting the size of the Flash player is as simple as setting the size of its container.

To put an instance of the Flash player on the page, simply create a new instance of `Y.SWF` and provide it with the reference to the container in which it should be placed, as well as the URL of the swf file that needs to be loaded:

``` YUI({...}).use('swf',function (Y) { // Default everything var myswf = new Y.SWF("#swfContainer", "http://example.com/example.swf"); }); ```

If you would like to specify additional parameters or pass arbitrary variables to the SWF, you can provide the constructor with the third argument, a paramter Object:

``` var params = {version: "9.0.115", fixedAttributes: {allowScriptAccess:"always", allowNetworking:"all"}, flashVars: {foo: "bar", foo1: "bar1"} }; var myswf = new Y.SWF("#swfContainer", "http://example.com/example.swf", params); ```

The parameter object may contain the following possible properties:

Property Description
`version` A period-delimited string of three numbers specifying the minimum version of Flash player that must be installed on the user's machine.
`fixedAttributes` An object with a set of configuration variables specific to the Flash player. The list of all possible configuration variables and their values, provided by Adobe, can be found here.
`flashVars` An object with a set of variables to pass to the Flash player. These variables are made available to the Flash application at initialization time, in the ActionScript's `Stage.loaderInfo.parameters` container.

Calling Methods on the instance of Flash player

The SWF Utility provides a wrapper for calling methods that have been exposed to JavaScript from within the Flash application. This allows the developer to call the methods without having to directly reference the private pointer to the instance of the Flash player contained in the SWF Utility. To call a method `foo(arg1, arg2)` on an instance of the Flash player, do the following: ``` YUI({...}).use('swf',function (Y) { var myswf = new Y.SWF("#swfContainer", "http://example.com/example.swf"); myswf.callSWF("foo", [arg1, arg2]); }); ```

Note that, since Flash player is run as a separate thread, the existence of its instance is not guaranteed when the method call on it is made. To make sure that Flash is ready to accept incoming method calls, it's best to have the Flash player make a call to JavaScript announcing that it has finished initializing. While there is a number of ways to do that, YUI hybrid components use the YUIBridge ActionScript library to automate this process. See the next section for notes on its usage.

Working with the YUIBridge ActionScript Library

NOTE: Due to security issues, as of 3.13.0, YUI has removed all the Flash files from the repository. Necessary source files and documentation for `YUIBridge` are available in the yui3-swfs repository.