在IE中显示透明：
<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/
cabs/flash/swflash.cab#version=6,0,29,0" width="770" height="148">
<param name="movie" value="swf/top.swf" />
<param name="quality" value="high" />
<param name="wmode" value="transparent" />
<embed src="swf/top.swf" quality="high" pluginspage="http://www.ma
cromedia.com/go/getflashplayer" type="application/x-shockwave-flash" width="770" height="148"></embed>
</object>
在FireFox中显示透明：！
<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cab
s/flash/swflash.cab#version=6,0,29,0" width="770" height="148">
<param name="movie" value="swf/top.swf" />
<param name="quality" value="high" />
<embed src="swf/top.swf" wmode="transparent" quality="high" pluginspage="http://www.macromedia.com/go/getflas
hplayer" type="application/x-shockwave-flash" width="770" height="148"></embed>
</object>
在两种浏览器中都显示透明：
<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockw
ave/cabs/flash/swflash.cab#version=6,0,29,0" width="770" height="148">
<param name="movie" value="swf/top.swf" />
<param name="quality" value="high" />
<param name="wmode" value="transparent" />
<embed src="swf/top.swf" wmode="transparent" quality="high" pluginspage="http://www.macromedia.com/go/getflashp
layer" type="application/x-shockwave-flash" width="770" height="148"></embed>
</object>
原来要在Embed标签下加上wmode="transparent”这个属性。