// prepare the form when the DOM is ready 
$(document).ready(function() { 
	$(".img_swap").hover(
          function(){this.src = this.src.replace("_off","_on");},
          function(){this.src = this.src.replace("_on","_off");
     });
	 $(".img-swap-1").hover(
          function(){this.src = this.src.replace("_off","_on");},
          function(){this.src = this.src.replace("_on","_off");
     });
	 var imgSwap = [];
	 $(".img_swap").each(function(){
		imgUrl = this.src.replace("_off","_on");
		imgSwap.push(imgUrl);
	});
	$(imgSwap).preload();
});
$.fn.preload = function() {
    this.each(function(){
        $('<img/>')[0].src = this;
    });
}