Firefox not displaying dynamically embedded flash? Page-speed might be your problem!

Flash no show

Today i discovered a worrying bug with Firefox, Firebug and Page-speed.  A good friend of mine, Chris Murray, was demonstrating his new flash photo upload applet. I rudely pointed out that it didn’t work in Firefox only to find out that it did in his. After wasting his time trying to prove SWFOject, Firefox and maybe Flash needed to be updated it turns out that no dynamically embedded flash worked in my version of Firefox. Sorry Chris…

What do i mean by embedded flash? Well, to get round the various methods of embedding flash into multiple browsers, javascript is often used to insert the flash into the DOM. Thereby using different techniques per browser.

To cut a long story short here is a screenshot of the relevant flash:

pageSpeedFlash

As you can see, the mark up is correct and present, just strangely disabled.

I am using Firefox 3.5.3, Firebug 1.4.3 and Page-speed 1.3. All are the updated and most recent versions.

What can you do?

Nothing really. The issue has been raised with Page-speed guys and there is a support thread too. I expect this to be resolved straight away as the issue has been marked critical. It is probably best to disable Page-speed for the time being. There is always Yslow!