Tab Panels JavaScript: Panel Initialization

  var tabSetList = document.getElementsByClassName('paragraph--type--horizontal-tabs');

  for (var set = 0; set < tabSetList.length; set++) {
    var tabList = new Array;
    var tabSections = tabSetList[set].children[0];

    for (var section = 0; section < tabSections.children.length; section++) {
      var headObj = tabPanel.children[0].children[0];
      var tabPanel = tabSections.children[section];

      /* Add every panel section heading to our tabList array */
      tabList.push(headObj.children[0].innerHTML);

      /* Hide the original heading */
      headObj.style.position = 'absolute';
      headObj.style.left = '-10000px';

      /* Set proper WAI-ARIA attributes on the tab panel */
      tabPanel.id = 'gtTab_' + set + '_' + section;
      tabPanel.setAttribute('role', 'tabpanel');
      tabPanel.setAttribute('aria-labelledby', 'gtTabTitle_' + set + '_' + section);
      if (section > 0) {
        tabPanel.style.display = 'none';
      }
    }