// show one, hide the rest

function tabs(aktivesTab) {

  var Tabs = new Array('page01','page02','page03','page04','page05','page06','page07','page08');

  for (i=0; i<Tabs.length; i++) {
    if (aktivesTab == Tabs[i]) {
      document.getElementById(Tabs[i]).style.visibility = 'visible';
      document.getElementById(Tabs[i]).style.display = 'block';
    }
    else {
      document.getElementById(Tabs[i]).style.visibility = 'hidden';
      document.getElementById(Tabs[i]).style.display = 'none';
    }
  }
}