<div style="position:relative;display:inline-block;178px;height:90px;z-index:9999;top:0;left:0;background-color:transparent;"></div>
<iframe src='' id='frame' frameborder='0' scrolling='no' width='178' height='90' allowTransparency='true' style='position:absolute;z-index:-1;top:0;left:0;padding:0px;margin:0px'></iframe>
ie7下div覆盖在iframe上方，ie8就不行，怎么解决
将透明的div层颜色加背景色或者加个透明的背景图