ajax 浏览器支持解决

function xmlHttp(){    xmlhttp = false;    xmlhttpObj = ["MSXML2.XmlHttp.5.0","MSXML2.XmlHttp.4.0","MSXML2.XmlHttp.3.0","MSXML2.XmlHttp","Microsoft.XmlHttp"];        if(window.XMLHttpRequest)    {        xmlhttp = new XMLHttpRequest();    }    else if(window.ActiveXObject)    {        for(i=0;i<xmlhttpObj.length;i++)            {            xmlhttp = new ActiveXObject(xmlhttpObj[i]);            if(xmlhttp)            {                break;                }        }    }    else    {        alert("暂时不能创建XMLHttpRequest对象");    }    return xmlhttp?xmlhttp:false;}