iframe 遮罩 object

.my_iframe {
position: absolute;
visibility: inherit;
top: 0;
left: 0;
width: auto;
z-index: -1;
filter: Alpha(Opacity = 0);
border-style: none;

}

<div><iframe class="my_iframe"></iframe></div>

或参见 http://blog.sina.com.cn/s/blog_665ad7770100qec8.html