docs: function getCallBack(onTimeOut){
          /*global callbackName, callback, scr, options;*/
          return function(){
              try {
                  if( onTimeOut ){
                      options.onfailure && options.onfailure();
                  }else{
                      callback.apply(window, arguments);
                      clearTimeout(timer);
                  }
                  window[callbackName] = null;
                  delete window[callbackName];
              } catch (exception) {
              } finally {
                  baidu.sio._removeScriptTag(scr);
              }
          }
      }