code: function(_id){
              var _conf  = _cache[_id],
                  _node1 = _e._$get(_id),
                  _node2 = _e._$get(_conf.xid);
              if (!_node1||!_conf) return;
              var _event = {
                  input:_node1.value
              };
              _event.length = _conf.onlength(_event.input);
              _event.delta = _conf.max-_event.length;
              _conf.onchange(_event);
              _node2.innerHTML = _event.value||('剩余'+Math.max(0,_event.delta)+'个字');
          }
docs: input change