<body onload="alert('complete')">如果是iframe
<script>
var doc=window.frames["f"].document;
function s(){
if (doc.readyState=="complete"){
alert("complete");
}
}
doc.onreadystatechange=s
</script>
<script>
var doc=window.frames["f"].document;
function s(){
if (doc.readyState=="complete"){
alert("complete");
}
}
doc.onreadystatechange=s
</script>
function window.onload(){
downloaded="downloaded";
}A中：
if(b.downloaded=="downloaded")
alert("B 已加载完毕");
alert("已加载完毕");