自动适应Iframe

function iframeAutoFit()
            {
              try
              {
                if(window!=parent)
                {
                  var a = parent.document.getElementsByTagName("IFRAME");
                  for(var i=0; i<a.length; i++) //www.deepteach.com
                  {
                    if(a[i].contentWindow==window)
                    {
                      var h = document.body.scrollHeight;
                      if(document.all) {h += 4;}
                      if(window.opera) {h += 1;}
                      a[i].style.height = h;
                    }
                  }
                }
              }
              catch (ex)
              {
                alert("脚本无法跨域操作！");
              }
            }
            //在子页面中增加
            if(document.attachEvent)
              window.attachEvent("onload",  iframeAutoFit);
            else
              window.addEventListener('load',  iframeAutoFit,  false);