code: function (cellTo, cellFrom) {
              if (UETable.isEmptyBlock(cellFrom)) return;
              if (UETable.isEmptyBlock(cellTo)) {
                  cellTo.innerHTML = cellFrom.innerHTML;
                  return;
              }
              var child = cellTo.lastChild;
              if (child.nodeType == 3 || !dtd.$block[child.tagName]) {
                  cellTo.appendChild(cellTo.ownerDocument.createElement('br'))
              }
              while (child = cellFrom.firstChild) {
                  cellTo.appendChild(child);
              }
          }
docs: 移动单元格中的内容