(function(){  var network = function(){      var monitor = this;              /**       * @param {Funcation} speedInterval       */      var speedInterval = null;      /**       * @param {Function} networkInterval       */      var networkInterval = null;      /**       * @param {Function} reNetworkInterval       */      var reNetworkInterval = null;      var time = 5000;               /**       * 获取网络连接状态       */      var getConnectState = function(){          return navigator.onLine ? 1 : 0;      };       /**       * 网络中断       */      var disconnect = function(){          // TODO ...           console.log("网速中断");          window.clearInterval(reNetworkInterval);          reNetworkInterval = null;                      endSpeed();          endNetwork();                      window.setTimeout(function(){              reNetworkInterval = window.setInterval(function(){                  if (getConnectState() == 1) {                      window.clearInterval(reNetworkInterval);                      reNetworkInterval = null;                      startSpeed();                      startNetwork();                  } else {                      window.clearInterval(reNetworkInterval);                      reNetworkInterval = null;                      disconnect();                  }              }, time);          }, 2 * time);      };          /**       * 网络速度       */      var speed = {              /**               * 网速过慢               */              bad : function(){                                                      // TODO ...                   console.log("网速过慢");                                      window.setTimeout(function(){                      if(getConnectState() == 1) {                          window.clearInterval(networkInterval);                          networkInterval = null;                          startSpeed();                      } else {                          disconnect();                      }                  }, 2 * time);              },              /**               * 网速中等               */              medium : function(){                                  // TODO ...                   console.log("网速中等");              },              /**               * 网速极佳               */              great : function(){                                  // TODO ...                   console.log("网速极佳");              }      };              /**       * 开启速度监测       * @private       */      var startSpeed = function(){                      window.clearInterval(speedInterval);          speedInterval = null;          if(getConnectState() == 1) {              speedInterval = window.setInterval(function(){                  var start = new Date().getTime();                  if (getConnectState() == 1) {                      var img = document.getElementById("networkSpeedImage");                      if (!!!img) {                          img = document.createElement("IMG");                          img.id = "networkSpeedImage";                          img.style.display = "none";                          document.body.appendChild(img);                      }                                              try {                          img.src = "http://www.baidu.com/img/baidu_jgylogo3.gif?_t=" + new Date().getTime();                          img.onload = function(){                              var end = new Date().getTime();                              var delta = end - start;                              if (delta > 200) {                                  speed.bad();                              } else if (delta > 100) {                                  speed.medium();                              } else {                                  speed.great();                              }                          };                      } catch(e){                          speed.bad();                      }                  } else {                      // TODO 网络断开                      disconnect();                  }              }, time);          }else {              // TODO 网络断开              disconnect();          }      };              /**       * 停止速度监测       * @private       */      var endSpeed = function(){          window.clearInterval(speedInterval);          speedInterval = null;      };              /**       * 开启网络连接监测       * @private       */      var startNetwork = function(){          if (getConnectState() == 1) {              networkInterval = window.setInterval(function(){                  if (getConnectState() == 0) {                      disconnect();                  }              }, time);          } else{              disconnect();          }      };              /**       * 结束网络连接监测       * @private        */      var endNetwork = function(){          window.clearInterval(networkInterval);          networkInterval = null;      };      /**       * 网络监控开始       */      this.start = function(){          startNetwork();          startSpeed();      };      /**       * 停止网络监控       */      this.stop = function(){          endSpeed();          endNetwork();      };  };       window.network = new network();  }).call(this);          // 调用的时候,直接调用network.start();