var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;

function checkForm(f) {
	if (f.name.value == "") {
		alert("Please enter your name.");
		f.name.focus();
		return false;
	}

	if (f.email.value == "") {
		alert("Please enter an email address.");
		f.email.focus();
		return false;
	}

	if (!reg.test(f.email.value)) {
		alert("The email address appears to be invalid");
		f.email.focus();
		return false;
	}

	if (f.message.value == "") {
		return confirm("You have not entered a message, are you sure you want to send the feedback?");
	}

	return true;
}