Recipe 3.1. Detecting the Player Version

Problem

You want to ensure that the user has the correct version of the Flash Player.

Solution

Use the Flash Player Detection Kit, available on Adobe's web site to check the version of player and, if necessary, initiate a player upgrade (http://www.adobe.com/software/flashplayer/download/detection_kit).

Discussion

Detecting the currently installed version of the Flash Player in the user's browser has been a problem for years, and there have been many solutions used by various developers. They generally fall into three categories:

• Browser-based script detection

• Server-side detection

• ActionScript detection

The first method uses JavaScript or VBScript to detect the version of the Flash Player the user has installed. Many of these scripts were prone to errors due to differences in platforms and browser types.

Server-side detection can be difficult if you don't have the ability to create server-side scripts.

Most ActionScript-based player detection techniques won't work directly in an ActionScript 3.0-based .swf. While ActionScript 1.0 and 2.0 had various object methods, variables, and functions that would return the player version, none of those are now valid in an ActionScript 3.0 class. ActionScript 3.0 has its own way of detecting the player versionthe flash.system.Capabilities.version property. This, of course, won't work at all with any version of the Flash Player prior to 8.5, so it is rather useless for Flash detection.

Adobe has researched all of these issues thoroughly, and came out with a Flash Player Detection Kit that guides you through the recommended procedures for best detecting the player version.

The kit includes documentation on the various issues and potential solutions, including sample VBScript and JavaScript for browser-based detection; .flas, .as, and .swf files for ActionScript detection; as well as ColdFusion and PHP scripts for server-side detection.

ActionScript-based detection works successfully as long as the user has any version of the Flash Player from Version 4 on up. Basically, it is a Flash 4 .swf that executes a script to detect the current player version; all you need to do is set your minimum content version as a variable in the script. If the player version is at least as high as the content version, it loads the specified content. If not, it redirects the browser to an alternate content page. This page can contain a lower version .swf, a non-Flash version of the content, or a notice instructing the user to upgrade his Flash Player, with a link to the player install page on Adobe's site.

Furthermore, the kit contains a .swf and HTML template that initializes an Express Install of the latest version of the Flash Player. If the user's player is not adequate, the browser is redirected to this .swf, which downloads the latest version of the Flash Player from Adobe's site, automatically installs it, and finally redirects the user back to the specified Flash content, all without the user ever leaving your site. This option requires that the user already have Version 6.0.65.0 of the Flash Player installed.

Using a combination of the techniques included in the Flash Player Detection Kit gives you very precise control over the Flash Player version and the content you deliver to your viewers.

For testing purposes, older versions of the Flash Player can be obtained from Macromedia's site (http://www.adobe.com/cfusion/knowledgebase/index.cfm?id=tn_14266).