iframe 自适应的使用

<!--引入foot-->
<iframe scrolling="no" id="iframepage" frameborder="0" src="foot.html" marginheight="0" marginwidth="0" width="100%" height="680px"></iframe>

<script type="text/javascript" language="javascript">
function iFrameHeight() {
var ifm = document.getElementById("iframepage");
var subWeb = document.frames ? document.frames["iframepage"].document : ifm.contentDocument;
if (ifm != null && subWeb != null) {
ifm.height = subWeb.body.scrollHeight;
ifm.width = subWeb.body.scrollWidth;
}
}
</script>