$(function(){
	var conf = {
		className : 'btn',
		postfix : '_on'
	};
	
	$('.' +conf.className).each(function(){
		this.originalSrc = this.src;
		this.rolloverSrc = this.originalSrc.replace(/(\.gif|\.jpg|\.png)/, conf.postfix+"$1");
		preloadImage(this.rolloverSrc);
	}).hover(function(){
		this.src = this.rolloverSrc;
	},function(){
		this.src = this.originalSrc;
	});
	
	$('.popup').click( function(){
		window.open(this.href, '', 'width=620, height=800, scrollbars=1, resizable=1');
		return false;
	});
	
});

preloadImages = [];
function preloadImage(url) {
	var p = preloadImages;
	var l = p.length;
	p[l] = new Image();
	p[l].src = url;
}