var time2=new Date();
document.write(" 当前页面执行用时<span style='color:#ff0000'>"+(time2-time1)/1000+"</span>秒");
function GetElementsByClassName(elementName,className)
{
    var allElements = document.getElementsByTagName(elementName);
    var elemColl = new Array();
    for (var i = 0; i< allElements.length; i++)
    {
         if (allElements[i].className.search('(^|\\s)' + className + '(\\s|$)') != -1)
         {
         elemColl[elemColl.length] = allElements[i];
         }
    }
    return elemColl;
}
if(document.getElementById("black") && document.documentElement)
{
var s=document.documentElement.clientHeight>=document.body.offsetHeight?document.documentElement.clientHeight:document.body.offsetHeight;
document.getElementById("black").style.height=s-225>0?s-225:0;
}