function email_valid(em) {
	// strip whitespace, validate email format
	em2 = (em.replace(/^\W+/,'')).replace(/\W+$/,'');
	re=/^[0-9a-zA-Z_-]+(\.[0-9a-zA-Z_-]+)*@[0-9a-zA-Z_-]+(\.[0-9a-zA-Z_-]+)+$/;
	return re.test(em2);
	}