www.123.com/a.html 框架iframe嵌入 000.123.com/b.html
页面域关系：
主页面a.html所属域A：www.123.com/a.html
被iframe的页面b.html所属域B：000.123.com,假设地址：http://000.123.com/b.html
实现效果：
A域下的页面1.html中通过iframe嵌入B域下的页面b.html,由于b.html的宽度和高度是不可预知而且会变化的,所以需要a.html中的iframe自适应大小.
问题本质:
js对跨域iframe访问问题,因为要控制a.html中iframe的高度和宽度就必须首先读取得到b.html的大小,A、B不属于同一个域,浏览器为了安全性考虑，使js跨域访问受限,读取不到b.html的高度和宽度.
解决方案:
引入代理代理页面c.html与a.html所属相同域A，c.html是A域下提供好的中间代理页面，假设c.html的地址：www.123.com/c.html,它负责读取location.hash里面的width和height的值,然后设置与它同域下的a.html中的iframe的宽度和高度.
A代码---------------------------------------------------------------------------------------------
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><title>主页面</title></head>
<body>
<div style="border:1px solid #ccc;padding:10px;">
<iframe id="frame_content" name="frame_content" src="http://000.123.com/b.html" width="100%" height="0" scrolling="no" frameborder="0"></iframe>
</div>
</body>
</html>
B代码---------------------------------------------------------------------------------------------
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><title>被iframe嵌套页面</title></head>
<body>
<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1
<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1
<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1<br>1
<iframe id="iframeC" name="iframeC" src="" width="0" height="0" style="display:none;" ></iframe>
<script type="text/javascript">
function sethash(){
hashH = document.documentElement.scrollHeight;
urlC = "http://www.123.com/c.html";
document.getElementById("iframeC").src=urlC+"#"+hashH;
}
window.onload=sethash;
</script>
</body>
</html>
C代码---------------------------------------------------------------------------------------------
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><title>中介页面</title></head>
<body>
<script>
function pseth() {
var iObj = parent.parent.document.getElementById('frame_content');
iObjH = parent.parent.frames["frame_content"].frames["iframeC"].location.hash;
iObj.style.height = iObjH.split("#")[1]+"px";
}
pseth();
</script>
</body>
</html>