code: function ($currentRoot, data) {
        data.relationship = data.relationship || '001';
        var $table = $('<table>')
          .append($('<tr>').append($('<td colspan="2">').append(this.createNode(data))))
          .append('<tr class="lines"><td colspan="2"><div class="downLine"></div></td></tr>')
          .append('<tr class="lines"><td class="rightLine"></td><td class="leftLine"></td></tr>');
        this.$chart.prepend($table)
          .children('table:first').append('<tr class="nodes"><td colspan="2"></td></tr>')
          .children('tr:last').children().append(this.$chart.children('table').last());
      }
docs: build the parent node of specific node