function checkSize(field) {
	if (document.getElementById(field)) {
		if (document.getElementById(field).value == 0) {
			alert("Por favor, seleccione un talle");
			return false;
		}
	}
	
	return true;
}

function swapImage(field, image_src) {
	document.getElementById(field).src = image_src;
}
function OpenWindow(page){
	var w = 500;
	var h = 400;

	var l = (screen.width - w) / 2;
	var t = (screen.height - h) / 2;

	var new_window_name=window.open(page,'','width='+w+',height='+h+',resizable=yes,scrollbars=yes,status=0,toolbar=no,left='+l+',top='+t);
	new_window_name.focus();
}