JavaScript loads the child page adaptive height of the IFRAME

Suppose the main page has a div with an iframe inside it:
<div id= "Framebox" >
<iframe id= "Framewin" src= "1.html" name= "Opwin" style= "width:100%;height:100%" frameborder= "0" scrolling= "no" > </iframe>
</div>

3 menu links, loading 1.html, 2.html, 3.html three pages in IFrame respectively. 3 subpages are loaded on their own page window.onload execution:
function aa () {
var newheight = document.body.scrollHeight + + "px";
Window.parent.document.getElementById ("Framebox"). Style.height = Newheight;
Above Firefox through, but IE6 must add the following sentence, otherwise the iframe height is changed, but the visible area has not changed
Window.parent.document.getElementById ("Framewin"). Style.height = Newheight;
}

JavaScript Tutorial Loading the sub-page adaptive height of an IFRAME