Ajax通过post传递多个参数

<script type="text/javascript">
/*
 * 获取ID方法
 */
function $cz(id){
   return document.getElementById(id);
};
/*
 * 创建XMLHttpRequest对象
 */
function createXMLHTTP(){ 
var getXMLHTTP;
if(window.ActiveXObject){
getXMLHTTP = new ActiveXObject("Microsoft.XMLHTTP");
}else {
getXMLHTTP = new XMLHttpRequest(); 
}
return getXMLHTTP;
};
/*
 * 创建函数
 */
function queryDate(){
var requestXMLHttp = createXMLHTTP();
if(requestXMLHttp){
 var url='Controller.php';
 var data="shop="+$cz('selquery').value+"&dateStart="+$cz('dateStart').value+"&dateEnd="+$cz('dateEnd').value; 
         requestXMLHttp.open("post",url,true);
         requestXMLHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");  //定义输出头 
         requestXMLHttp.send(data);
         requestXMLHttp.onreadystatechange=function (){
                 if(requestXMLHttp.readyState==4){
                     var getVal = requestXMLHttp.responseText;
                         alert(getVal);
                     }
             };
         
}
};
</script>