<body>
<div id="load" align="center">
<img src="http://sc.cnwebshow.com/upimg/allimg/070707/01294420.gif" /> loading...
</div> <!-- 首先放一个div,用做loading效果 -->
<iframe id="demo" src="http://www.baidu.com/" width="100%" height="100%" frameborder="0" scrolling="no" marginheight="0"></iframe> <!-- src 里面放你想要的网页-->
<script type="text/javascript">
//<![CDATA[
var a = document.getElementById("demo");
var b = document.getElementById("load");
a.style.display = "none"; //隐藏
b.style.display = "block"; //显示
a.onreadystatechange = function() {
if (this.readyState=="complete") { //最近才知道的。不然也写不出来。
// 解释:一个iframe加载完毕的状态是complete,
// 就象xmlhttp里的那个==4一样,这些都是规定的...
b.innerHTML = "load complete!";
b.style.display = "none";
a.style.display = "block";
}
}
//]]>
</script>
</body>

if (state == " loaded " || state == " interactive " || state == " complete " ) {
this .onreadystatechange = null ;
b.innerHTML = "load complete!";
b.style.display = "none";
a.style.display = "block";
if ( window.onload )
{
alert( "page onload." );
}
else{
window.setTimeout( on, 1000);
}
}
on();