// <![CDATA[
function rollover() {
  if (!document.getElementById) return
  var imgPreload = new Array();
  var images = document.getElementsByTagName('img');
  var i = 0;
  var under;
  var over;
  while (i < images.length) {
    if (images[i].getAttribute('alt')) {
	  if ((images[i].getAttribute('alt')).substr(0,5) == 'menu_' &&
	      (images[i].getAttribute('src')).substr(-9,9) != '_over.gif') {
         imgPreload[i] = new Image();

	 under = 'images/' + images[i].getAttribute('alt') + '.gif';
	 imgPreload[i].setAttribute('src', under);

         images[i].onmouseover = function() {
	   over = 'images/' + this.getAttribute('alt') + '_over.gif';
	   this.setAttribute('src', over);
         }
         images[i].onmouseout = function() {
	   under = 'images/' + this.getAttribute('alt') + '.gif';
           this.setAttribute('src', under);
	 }   
      }
    }
	i++;
  }
}
// ]]>