javascript - 封装ajax

封装，使用有示例.

    // 封装示例：
    function ajax(url, method, params, done) {
      var xhr = null;
      method = method.toUpperCase();
      xhr = window.XMLHttpRequest ? xhr = window.XMLHttpRequest : xhr = new ActiveXObject('Microsoft.XMLHTTP');

      if (typeof params === 'object') {
        var tempArr = [];
        for (var key in params) {
          var value = params[key];
          tempArr.push(key + '=' + value);
        }
        params = tempArr.join('&');
      }

      // GET
      if (method === 'GET') {
        url += '?' + params;
      }
      xhr.open(method, url, false);

      // POST
      var data = null;
      if (method === 'POST') {
        xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        data = params;
      }

      xhr.onreadystatechange = function () {
        if (this.readyState !== 4 && this.status !== 200) return false;
        ongone(this.responseText);
      }
      xhr.send(data);
    }


    // 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     }