js实现ajax

function sendPhoneNumber(){var phoneNo=document.getElementById("contactNumber").value;var orderId=${orderid};var format=/^\d+$/;if(!format.test(phoneNo)){alert("请输入正确电话号码");return;}else{ createXMLRequest(); var url = "remindBillPhone.action?contactNumber="+phoneNo+"&orderId="+orderId;   request.open("POST", url, true);            request.onreadystatechange = sendAndGetRequest;           request.send(null);}}var request=false;function createXMLRequest() {try {                request = new ActivexObject("Msxml2.XMLHTTP");}           catch (e1) {               try {                    request = new ActivexObject("Microsoft.XMLHTTP");  }               catch (e2) {                   request = false;               }           }            if (!request && typeof XMLHttpRequest != 'undefined') { request = new XMLHttpRequest();          }                  }function sendAndGetRequest(){if (request.readyState == 4) {  var json=eval("("+request.responseText+")"); if(json.success==false){alert(json.message);}else{ alert(json.message); closeDialog();}}}