function DisableCheckout(evt, elem) {
	var key = (window.Event) ? evt.which : evt.keyCode;
	MarkChange();
	if (key == 13) {
		return false;
	}
	else {
		$show('CheckoutDisabled');
		if(elem.value==""){
		    $show('QuantityGreaterThanZero');
		}
		var Checkout1 = document.getElementById('Checkout1');
		if (Checkout1 != null) {
			Checkout1.disabled = 'true';
		}
		var Checkout2 = document.getElementById('Checkout2');
		if (Checkout2 != null) {
			Checkout2.disabled = 'true';
		}
	}
	return true;
}
function MarkChange() {
	var elements = document.getElementsByTagName('*');
	for (var i = 0; i < elements.length; i++) {
		var id = elements[i].getAttribute('id');
		if (id != null && (id.match('updateRequired') != null)) {
			var updateRequired = document.getElementById(id);
			updateRequired.value = '1';
		}
	}
}