code: function findHandlers( arr, name, callback, context ) {
              return $.grep( arr, function( handler ) {
                  return handler &&
                          (!name || handler.e === name) &&
                          (!callback || handler.cb === callback ||
                          handler.cb._cb === callback) &&
                          (!context || handler.ctx === context);
              });
          }
docs: 根据条件过滤出事件handlers.