This is different than the default code that Flash provides. That typically involves the <embed> tag and is not valid XHTML. This doesn't use that, and is fully valid
<object type="application/x-shockwave-flash"
data="your-flash-file.swf"
width="0" height="0">
<param name="movie" value="your-flash-file.swf" />
<param name="quality" value="high"/>
</object>