var tabs5 = new Array("tab18", "tab19", "tab20", "tab21");
  function displayTab5(tabName) {
    for ( i = 0; i < tabs5.length; i++ ) {
      var tab = document.getElementById(tabs5[i]);
      if ( tabName == tabs5[i] ) {
        tab.style.display = 'inline';
      } else {
        tab.style.display = 'none';
      }
    }
  }