code: function () {
              var rows = this.table.rows, maxLen = 0, cellRows = {};
              for (var i = 0, row; row = rows[i]; i++) {
                  var cellsNum = 0;
                  for (var j = 0, cj; cj = row.cells[j++];) {
                      cellsNum += (cj.colSpan || 1);
                      if (cj.rowSpan && cj.rowSpan > 1) {
                          for (var k = 1; k < cj.rowSpan; k++) {
                              if (!cellRows['row_' + (i + k)]) {
                                  cellRows['row_' + (i + k)] = (cj.colSpan || 1);
                              } else {
                                  cellRows['row_' + (i + k)]++
                              }
                          }
  
                      }
                  }
                  cellsNum += cellRows['row_' + i] || 0;
                  maxLen = Math.max(cellsNum, maxLen);
              }
              return maxLen;
          }
docs: 获取当前表格的最大列数