function setup(off_images, on_images) {
 off_images = off_images;
 on_images = on_images;

 this.images = new Array();
 this.imagesX = new Array();
	/*alert(off_images.length);*/  
 for (var i=0; i<off_images.length;++i) {
  images[i] = new Image();
  imagesX[i] = new Image();	
  images[i].src = off_images[i];
  imagesX[i].src = on_images[i];	
 }
}

function swap(number,on) {
 if (document.images) {
  if(on) {
   document["image"+number].src = this.imagesX[number].src;
  }
  else {
   document["image"+number].src = this.images[number].src;
  }
 }
}