====== ajaxRequest-基于jq二次封装ajax请求 ======

===== 使用说明 =====
  /**
   * 基于jq二次封装ajax请求，方便对返回的信息进行全局处理
   * @param callback
   */
  function ajaxRequest(callback) {
      var _this = this;
      this.ajaxParam = {
          type: callback.type ? callback.type : "get",
          success: function (data) {
              console.log(data)
              if (callback.success) {
                  if (data.code === 0) {
                      callback.success(data);
                  } else if (data.code === -2) {
                      layer.alert(data.msg, {
                          icon: 5
                      });
                      callback.success(data);
                  } else {
                      layer.alert(data.msg, {
                          icon: 5
                      });
                      callback.success(data);
                  }
              }
          },
          error: function (err) {
              console.log(err)
              layer.alert("网络连接出错！", {
                  icon: 5
              });
              if (callback.error) {
                  callback.error(data);
              }
          },
          beforeSend: function () {
              if (callback.beforeSend) {
                  callback.beforeSend();
              }
          },
          complete: function (XMLHttpRequest, textStatus) {
              if (callback.complete) {
                  callback.complete(XMLHttpRequest, textStatus)
              }
          }
      };
  
      for (var key in callback) {
          if (!this.ajaxParam[key]) {
              this.ajaxParam[key] = callback[key];
          }
      }
  
      this.destroy = function() {
          _this.ajaxParam = null;
          _this = null;
      };
  
      $.ajax(this.ajaxParam);
  }