var timer;
 var isNS4 = (document.layers) ? true : false; // NS>=4.0
 var isIE4 = (document.all) ? true : false; // IE>=4.0
 var isW3C = (document.getElementById) ? true : false; // IE>=5.0 & NN>=6.0

 function setVisible(id) {
  done('subevents');
  done('subfacilities');
  done('subpresenter');
  done('subcommunity');
  clearTimeout(timer);
  if (isNS4) document.layers[id].visibility = "show"; 
  if (isIE4) eval(id+'.style.visibility = "visible"');
  if (isW3C) document.getElementById(id).style.visibility="visible";
 }

 function setInvisible(id) {
  timer = setTimeout("done('" + id + "')",250);
 }
 
 function done(id) {
  if (isNS4) document.layers[id].visibility = "hide"; 
  if (isIE4) eval(id+'.style.visibility = "hidden"');
  if (isW3C) document.getElementById(id).style.visibility="hidden";
 }