function initRollOverImages() {
var image_cache = new Object();
  jQuery(".swap").each(function(i) {
    var imgsrc = this.src;
    var dot = this.src.lastIndexOf('.');
    var imgsrc_on = this.src.substr(0, dot) + '_on' + this.src.substr(dot, 4);
 
    image_cache[this.src] = new Image();
    image_cache[this.src].src = imgsrc_on;
    jQuery(this).hover(
      function() { this.src = imgsrc_on; },
      function() { this.src = imgsrc; }
    );
  });
}
// JavaScript Document