function preload() {
   if (document.images) {
      for (var i = 0; i < preload.arguments.length; i++) {
         this[i+1] = new Image();
         this[i+1].src = preload.arguments[i];
      }
   }
}

function show(i,newsrc) {
   if (document.images) {
      document.images[i].src = newsrc ;
   }    
}

function popup(url,w,h,args) {
   window.open(url,'_blank','height='+h+',width='+w+','+args);
}