Iframe自适应高度

正在踌躇的时候发现下面的这段代码，终于得意解决。苦于对js没有足够的熟悉，代码中的具体方法参数还得继续学习，感谢提供代码的朋友。
function SetCwinHeight()
{
var cwin=document.getElementById("cwin");
if (document.getElementById)
{
if (cwin && !window.opera)
{
if (cwin.contentDocument && cwin.contentDocument.body.offsetHeight)
cwin.height = cwin.contentDocument.body.offsetHeight;
else if(cwin.Document && cwin.Document.body.scrollHeight)
cwin.height = cwin.Document.body.scrollHeight;
}
}
}

<iframe width="778" align="center" height="200" id="cwin" name="cwin" onload="Javascript:SetCwinHeight(this)" frameborder="0" scrolling="no"></iframe>

function SetCwinHeight(obj)
{
  var cwin=obj;
  if (document.getElementById)
  {
    if (cwin && !window.opera)
    {
      if (cwin.contentDocument && cwin.contentDocument.body.offsetHeight)
        cwin.height = cwin.contentDocument.body.offsetHeight;
      else if(cwin.Document && cwin.Document.body.scrollHeight)
        cwin.height = cwin.Document.body.scrollHeight;
    }
  }
}

引用时
onload="javascript:SetCwinHeight(this)"