Ajax系列(二)

创建 XMLHttpRequest

<script language="javascript" type="text/javascript">
   var request = false;
   try {
     request = new XMLHttpRequest();
   } catch (trymicrosoft) {
     try {
       request = new ActiveXObject("Msxml2.XMLHTTP");
     } catch (othermicrosoft) {
       try {
         request = new ActiveXObject("Microsoft.XMLHTTP");
       } catch (failed) {
         request = false;
       }  
     }
   }

   if (!request)
     alert("Error initializing XMLHttpRequest!");

   function getCustomerInfo() {
     var phone = document.getElementById("phone").value;
     var url = "/lookupCustomer.jsp?phone=" + escape(phone);
     request.onreadystatechange = updatePage;
     request.open("GET", url, true);
     
     request.send(null);
   }
/**回调方法,每次状态码改变都会被调用*/
  function updatePage() {
     if (request.readyState == 4) {
       if (request.status == 200) {
         var response = request.responseText.split("|");
         document.getElementById("order").value = response[0];
         document.getElementById("address").innerHTML =
           response[1].replace(/\n/g, "");
       } else
         alert("status is " + request.status);
     }
   }
</script>