跨浏览器创建XMLHttpRequest对象

综合考虑Internet Explorer和非Internet Explorer浏览器这两种情况:

<script type="text/javascript">
function createXMLHttpRequest(){
    var xmlHttp;
    if(window.XMLHttpRequest){
        xmlHttp=new XMLHttpRequest();
    }else if(window.ActiveXObject){
        try{
            xmlHttp=new ActiveXObject("Msmxl2.XMLHTTP");
        }catch(e){
            xmlHttp=new ActiveXObject("Microosoft.XMLHTTP");
        }
    }
    return xmlHttp;
}
</script>