I think the problem is not that IE does not support a search on <embed> tags but rather that in IE one uses <object> tags to include a flash element. As a matter of fact, Firefox also supports the latter format, if you use the following form:
<object type="application/x-shockwave-flash" data="MyFlashProgram.swf">
In fact, this is the preferred syntax, and swfobject uses this as well. So, for a cross-browser solution, you'd need to look for:
- <embed> and <object> elements with
type
attribute set to "application/x-shockwave-flash"
- <object> elements with
classid
attribute set to "clsid:D27CDB6E-AE6D-11cf-96B8-444553540000"
Im unsure about other browsers like Opera or Safari, it is possible that you need to extend this list with further variants.
Finding these elements should be trivial with a javascript library like jQuery or prototype, but you can manage without those.