docs: function createTR(that, trid) {
          var tr, sep;
          tr = document.createElement('tr');
          that.table.appendChild(tr);
          // Set id.
          sep = that.separator;
          tr.id = that.id + sep + 'tr' + sep + trid;
          // Store reference.
          that.trs.push(tr);
          return tr;
      }