原生js实现ajax 发送post请求

var postData = { "name1": "value1", "name2": "value2"};
postData = (function(obj){
// 转成post需要的字符串.
var str = "";

for(var prop in obj){

str += prop + "=" + obj[prop] + "&"

} return str;})(postData);

var xhr = new XMLHttpRequest();
xhr.open("POST", "../module", true);
xhr.setRequestHeader("Content-type","application/x-www-form-urlencoded");
xhr.onreadystatechange = function(){ var XMLHttpReq = xhr; if (XMLHttpReq.readyState == 4) { if (XMLHttpReq.status == 200) { var text = XMLHttpReq.responseText; console.log(text); } }};
xhr.send(postData);