function changeMainImg(obj) {
	var z = document.getElementById("zoom1");
	var mi = z.getElementsByTagName("img")[0];
	var w = parseInt(obj.getAttribute("pw"));
	var h = parseInt(obj.getAttribute("ph"));
	var im = obj.getAttribute("rev");
	if (w > h ) {
		mi.width = "270";
		mi.height = Math.ceil(h * 270 / w);
	} else {
		mi.width = Math.ceil(w * 270 / h);
		mi.height = "270";
	}
	mi.src = im;
	return false;
}