// ================== auth/login.phtml ==================
/**
 * check the ligality of the form value.
 * 
 * @param f
 *            the form to be checked.
 * @return true if legal, false if illegal.
 */
function checkPostForm(f) {
	// check username
	if (f.username.value.trim() == "") {
		alert(msgNotEmpty("Username"));
		return false;
	}
	// check password
	if (f.password.value.trim() == "") {
		alert(msgNotEmpty("Password"));
		return false;
	}

	return true;
}