试试：
iframe.contentwindow.document.documentElement.innerHTML
document.getElementById("MyIFrame").contentDocument.getElementById("s").style.color="blue";详细代码如下:
TestIFrame.htm: <html>
<head>
<script type="text/javascript">
function f(){
var doc; if (document.all){//IE
doc = document.frames["MyIFrame"].document;
}else{//Firefox
doc = document.getElementById("MyIFrame").contentDocument;
} doc.getElementById("s").style.color="blue";
}
</script>
</head>
<body onload="f()"> <iframe id = "MyIFrame" name = "MyIFrame" src = "MyIFrame.htm" width = "100" height="100"> </body>
</html> MyIFrame.htm: <h1 id = "s" style="color:red;" >内容<h1>
