javascript - 封装ajax

封装，使用有示例.

 1     // 封装示例：
 2     function ajax(url, method, params, done) {
 3       var xhr = null;
 4       method = method.toUpperCase();
 5       xhr = window.XMLHttpRequest ? xhr = window.XMLHttpRequest : xhr = new ActiveXObject('Microsoft.XMLHTTP');
 6 
 7       if (typeof params === 'object') {
 8         var tempArr = [];
 9         for (var key in params) {
10           var value = params[key];
11           tempArr.push(key + '=' + value);
12         }
13         params = tempArr.join('&');
14       }
15 
16       // GET
17       if (method === 'GET') {
18         url += '?' + params;
19       }
20       xhr.open(method, url, false);
21 
22       // POST
23       var data = null;
24       if (method === 'POST') {
25         xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
26         data = params;
27       }
28 
29       xhr.onreadystatechange = function () {
30         if (this.readyState !== 4 && this.status !== 200) return false;
31         ongone(this.responseText);
32       }
33       xhr.send(data);
34     }
35 
36 
37     // 调用示例：ajax('get','test.php',{id:123,},ongone)
38     ajax('GET', 'test.php', {}, ongone);
39 
40     var ongone = function (res) {
41       console.log('1');
42       console.log('2');
43       console.log(res);
44       console.log('gone!');
45     }