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Flash Detection

What's Flash detection?

Flash detection usually refers to using some kind of script or plugin to "detect" whether or not your user has the Flash player installed on their system, and then displaying alternative content if they don't. For example, if a user doesn't have the Flash player (or their version of the Flash player is too old), you might want them to go to a different page that has a non-Flash version of your site. Or, you might want to have a static image show up in place of the Flash movie.

Limitations of Flash detection

Because of the many varieties of browsers and their various security options, there is no way to detect if Flash will work 100% of the time. No script or solution exists that will work for every combination of browsers and options, especially as technologies change. Inevitably you will probably run into someone who was unable to view your site content because the Flash detection failed.

Internet Explorer's special issues

In fact, many web developers are running into the issue of people who use Internet Explorer at "high" security settings, which block all "Active-X components" from running -- including Flash movies. Thus, a script might detect that a user has the correct Flash player installed, but then IE makes that a moot point by blocking the Flash movie anyway. This has become more of an issue since the release of Windows Service Pack 2, which automatically sets IE security settings at "high." (Note: There is hope for people who want to use Flash detection for this issue! See the FlashObject solution below.)

What's a Web Developer to do?

Colin Moock at moock.org offers these helpful things to consider when building a web site and considering the use of Flash:

• Detection schemes generally only work about 90-97% of the time (that percentage is not the result of a scientific study, it's a general empirical feel)
• Consider not using Flash detection at all. The best solution is probably to offer a splash page that provides links to both the Flash and non-Flash version of your content. This is easy to implement and guaranteed to work.
• If only part of a page is in flash, and you don't want to redirect to another page when the user does not have flash, then choose one of the following approaches:
  • Don't do detection. Let the browser either install Flash automatically or redirect the visitor to a Flash installation page
  • Don't use Flash. If you can't accept the browser-install process, then maybe you shouldn't use Flash at all.
  • Use a detection script. Again, the problem with this approach is that detection scripts sometimes fail, so some of your users will be stranded.
• Always provide a direct link to your Flash content from key pages on your site. This acts as a manual-override that savvy visitors can use to access your content even when detection doesn't work
• If you use detection, provide a direct link to your Flash content on all non-Flash pages

Available Flash Detection Solutions

If you decide that Flash detection is worth it (for example, you would rather not maintain two copies of your site), there are several available Flash detection solutions out there, and we've listed some of the more well-known below:

FlashObject embed: An elegant piece of scripting by Geoff Stearns. Read his explanations about his original version and the newest updated version. We like this one because it's been tested in Firefox, Mozilla, Safari, IE 5+, Opera (6 & 7), and Camino, works with IE's "high security" settings by embedding the alternative content, and even provides a link to bypass the detection for people who should be able to view the Flash but for one reason or another, didn't get to it immediately. Stearns' method of using a <div> to hold the alternate content allows search engines to get to the content, and his clean functions make this method extremely easy to use.

Moock Flash Player Inspector: Colin Moock was one of the originals who put together Flash detection scripts, and his method is still instructive for people wanting to learn how to use Javascript to detect Flash. The script works for most browsers but fails for people who use IE at high security settings. (Our old Flash detection article was based on the Moock FPI.)

Macromedia Flash Detection Kit Macromedia has put together a simple package for detecting Flash that does not depend on Javascript. Their kit includes an .swf which you would embed on a page, then set two variables for the Flash page link and non-Flash page link (either in the HTML, in Dreamweaver, or in the Flash movie itself, depending on which version you use). Their solution seems odd (using a Flash movie to detect Flash?) but it works -- except, again, for IE high security setting issues.

Links

Macromedia's Flash Player Uninstaller

http://www.kirupa.com/developer/mx/detection.htm - Another Flash detection method (javascript-based) that works for IE security settings

http://www.macromedia.com/cfusion/knowledgebase/index.cfm?id=tn_14526 Macromedia's article about Flash detection

http://www.macromedia.com/cfusion/knowledgebase/index.cfm?id=tn_19542 Macromedia's tech note about Windows Service Pack 2