function clickTab(alink) {
  var myli = alink.parentNode;
  var myParent = myli.parentNode;

  var liList = myParent.getElementsByTagName("LI");

  for (i=0; i<liList.length; i++) {
    var block = document.getElementById(liList[i].id.substr(1));
    if ( block!=null ) {
	    if (liList[i].id == myli.id) {
	      liList[i].className="on";
	      block.style.display='block';
	    } else {
	      liList[i].className="";
	      block.style.display='none';
	    }
	}
  }
}