原生javascript实现ajax,post参数

 1  var json = {
 2           userid: userid,
 3           cid: cid,
 4           openid: openid,
 5           type: 1
 6         };
 7         //    原生ajax
 8         json = (function(obj){ // 转成post需要的字符串.
 9           var str = "";
10           for(var prop in obj){
11             str += prop + "=" + obj[prop] + "&"
12           }
13           return str;
14         })(json);
15 var xhr = new XMLHttpRequest();
16         xhr.open("POST", "/sharecount", true);
17         xhr.setRequestHeader("Content-type","application/x-www-form-urlencoded");
18         xhr.onreadystatechange = function(){
19           var XMLHttpReq = xhr;
20           if (XMLHttpReq.readyState == 4) {
21             if (XMLHttpReq.status == 200) {
22               //不做处理
23             }
24           }
25         }
26         xhr.send(json);