code: function tableBorderDrag( evt ) {
  
          isInResizeBuffer = false;
  
          startTd = evt.target || evt.srcElement;
          if( !startTd ) return;
          var state = getRelation(startTd, mouseCoords(evt));
          if (/\d/.test(state)) {
              state = state.replace(/\d/, '');
              startTd = getUETable(startTd).getPreviewCell(startTd, state == 'v');
          }
          hideDragLine(me);
          getDragLine(me, me.document);
          me.fireEvent('saveScene');
          showDragLineAt(state, startTd);
          mousedown = true;
          //拖动开始
          onDrag = state;
          dragTd = startTd;
      }
docs: 边框拖动