Ajax 的格式

  var XMLHTTP;
    function createXMLHttpRequest()   //创建AJAX
    {
    if(window.ActiveXObject)
    {
    XMLHTTP=new ActiveXObject("Microsoft.XMLHTTP");
    }
    else if(window.XMLHttpRequest)
    {
    xmlHttp=new XMLHttpRequest();
    }
    }
    
    
    function  startRequest(url)  //开始AJAX
    {
   
    createXMLHttpRequest();     
    XMLHTTP.onreadystatechange=handleStateChange;
    XMLHTTP.open("GET",url,true);
    XMLHTTP.send(null);
    
    }
    
    function handleStateChange()
    { 
    if(XMLHTTP.readyState==4) {
    alert(XMLHTTP.status);
       if(XMLHTTP.status==200){
   
      PanduanBackZhi();
   }  
    }
    }
   
   
   function PanduanBackZhi()
   {
   if(XMLHTTP.responseText=="从数据库载出")
   {
   document.getElementById('Xianshi').innerHTML="<img border=\"0\" src=\"../images/ajaxloading.gif\"><font color=#FF0000 sytle=font-weight:bold>准备从SQL导出数据,请稍等......</font>";
   document.getElementById('Button2').disabled=false;
   }
   
    if(XMLHTTP.responseText=="从EXCEL 导出")
   {
   document.getElementById('Xianshi').innerHTML="<img border=\"0\" src=\"../images/ajaxloading.gif\"><font color=#FF0000 sytle=font-weight:bold>准备DATATABLE导出数据,请稍等......</font>";
   document.getElementById('Button1').disabled=false;
   }
   }
   
   function Diaoyong(panduan)
   {
   startRequest("../AJAXExcel.aspx?id="+panduan+"");
   }