ajax 示例代码

        var xmlHttp = false;
        try {
          xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e) {
          try {
            xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
          } catch (e2) {
            xmlHttp = false;
          }
        }
        if (!xmlHttp && typeof XMLHttpRequest != '0') {
          xmlHttp = new XMLHttpRequest();
        }

         function callServer(unitcode) 
         {
                
              //if ((unitcode == null) || (unitcode == "")) return;
              alert("调用了callServer");
              var url = "Login.aspx?unitcode=" + unitcode+"";
              xmlHttp.open("GET", url, true);
              xmlHttp.onreadystatechange = updatePage;
              xmlHttp.send(null);
         }

        function updatePage() {
          if (xmlHttp.readyState < 4) {
//            document.getElementById("TipName").innerText="0";
//            window.status="处理中...!";
          }
          if (xmlHttp.readyState == 4) {
//            var data = xmlHttp.responseText;
//            document.getElementById("TipName").innerText=data;
            //window.status=data;
          }
//          document.getElementById(TxtName_Var).innerText=document.getElementById("TipName").value;
        }