flex 背景色透明

把app的backgroundAlpha设成0，然后在装载这个swf的html文件添加这句
<param name="wmode" value="transparent">
到那些<param>标签附近

<script type="text/javascript" src="swfobject.js"></script>
<script type="text/javascript">
    var width=800;
    var height=80;
    var flashVersion = "9,0,124,0";
    var movie = "uploadfldh.swf";
    var movieName = "flashMovie";
    var bgColor = "#000000";
    var express = "expressinstall.swf";
    var replaceDiv = "flashcontent";

    var flashvars = {}; 
   
flashvars.fileFilters="PowerPoint 演示文稿(*.ppt, *.pptx)^*.ppt; *.pptx|Microsoft Office Word 文档(*.doc, *.docx)^*.doc; *.docx";

    flashvars.requestAuthURL = "aa1.do?action=uploadres";
    flashvars.resid = '<%=request.getAttribute("resid")%>';
   
    var params = {wmode:"transparent"};
    var attributes = {};
    attributes.id = movieName;

    swfobject.embedSWF(movie, replaceDiv, width, height, flashVersion, express, flashvars, params, attributes);

</script>