function changeImg(img, pic, txt) {
	$(pic.id).src = 'img/home/'+img;
	$('rollover-text').innerHTML = txt;
}
function changeHero(img, link, tag) {
	$('hero_link').href = link
	$('hero_link').down('img').src = 'img/home/'+img;
	for (var i=0; i < document.getElementsByClassName('pic').length; i++) {
		document.getElementsByClassName('pic')[i].className = "pic";
	};
	$(tag.id).className = "pic active";
}