Event.observe(window, 'load', function() {
	var enable = false;
	
	Event.observe(document.forms[0], 'submit', function (e) {
		enable = $$('input[type=text]').all( function(n) { return (n.value.length > 0); });
		if (!enable)
		{
			Event.element(e).action = './cart.php'
			alert('Please enter a quantity.');
			Event.stop(e);
		}
	});
});