function emailCheck(el) {

	var emailStr = el;

	var emailPat = /^[\'_\.0-9A-Za-z-]+@([0-9A-Za-z-]+[0-9A-Za-z-\.]+)\.([A-Za-z]){2,4}$/;

	var email = emailStr.toLowerCase();

	var matchArray = email.match(emailPat);

	if (matchArray==null) {

		return false;

	}

	return true;

}