docs: function UNavLayoutTab(tab, tabs, panels, layout) {
  
      /**
       * Auxiliary method to programmatically select a tab in the UI.
       */
      function selectTab() {
          var href = tab.href.split('#')[1];
          var panel = layout._content.querySelector('#' + href);
          layout._resetTabState(tabs);
          layout._resetPanelState(panels);
          u.addClass(tab, layout._CssClasses.IS_ACTIVE);
          u.addClass(panel, layout._CssClasses.IS_ACTIVE);
      }
  
      //if (layout.tabBar_.classList.contains(layout._CssClasses.JS_RIPPLE_EFFECT)) {
      var rippleContainer = document.createElement('span');
      u.addClass(rippleContainer, 'u-ripple');
      //rippleContainer.classList.add(layout._CssClasses.JS_RIPPLE_EFFECT);
      //var ripple = document.createElement('span');
      //ripple.classList.add(layout._CssClasses.RIPPLE);
      //rippleContainer.appendChild(ripple);
      tab.appendChild(rippleContainer);
      new URipple(tab)
      //}
      u.on(tab,'click', function (e) {
          if (tab.getAttribute('href').charAt(0) === '#') {
              e.preventDefault();
              selectTab();
          }
      });
  
      tab.show = selectTab;
  
      u.on(tab,'click', function (e) {
          e.preventDefault();
          var href = tab.href.split('#')[1];
          var panel = layout._content.querySelector('#' + href);
          layout._resetTabState(tabs);
          layout._resetPanelState(panels);
          u.addClass(tab, layout._CssClasses.IS_ACTIVE);
          u.addClass(panel, layout._CssClasses.IS_ACTIVE);
      });
  }