// test with <input[^>]*name=['"][^'"]*[Ee][Mm][Aa][Ii][Ll][^'">]*['"]
function isValidEmail(email) {
	rexp = /^[-a-zA-Z0-9_]+(\.[-a-zA-Z0-9_]+)*@[-a-zA-Z0-9_]+(\.[-a-zA-Z0-9_]+)+$/
	if (typeof(email) == "string") {
		return rexp.test(email);
	} else {
		return rexp.test(email.value);
	}
}