1.5基础库wx.createSelectorQuery() 没用啦

  var query = wx.createSelectorQuery()
    query.selectViewport().scrollOffset();
    query.exec(function (res) {      //res返回值为null
      console.info(res);
      scrollTop = res[0].scrollTop // 显示区域的竖直滚动位置
      that.data.scrollTop = scrollTop;
    })