关闭一个页面时不弹出对话框

function CloseWin()
{
    var ua = navigator.userAgent; var ie = navigator.appName=="Microsoft Internet Explorer"?true:false;
    if(ie)
    {
       var IEversion = parseFloat(ua.substring(ua.indexOf("MSIE ")+5,ua.indexOf(";",ua.indexOf("MSIE "))));
       if( IEversion< 5.5)
       {
         var str = '';
         document.body.insertAdjacentHTML("beforeEnd", str);
         document.all.noTipClose.Click();
       }
       else
       {
        window.opener =null; window.close();
       }
    }
    else
    {
      window.close()
    }
}