Make a Flash SWF Background Transparent

To make the background of a Flash .swf transparent, simply place two small pieces of code into your HTML.
First you need to insert a parameter setting after the object tag:

<param name=”wmode” value=”transparent” />

Next, you’ll need to insert a little extra code inside the embed src tag.  Place the following after your quality setting:

wmode=”transparent”

Sometimes after you make this change, your webpage may still display improperly until you resave the web page and possibly clear your browser’s cache.
However, the two above pieces of code will definitely make your .swf’s background transparent.