function validate(f) {
	if (isBlank(f.forename.value)) {
		alert("You must enter a forename");
		f.forename.focus();
		return false
	}
	if (isBlank(f.surname.value)) {
		alert("You must enter a surname");
		f.surname.focus();
		return false;
	}
	if (isBlank(f.email.value)) {
		alert("You must enter a email");
		f.email.focus();
		return false;
	}
	if (!isEmail(f.email.value)) {
		alert("You have supplied an invalid email address!");
		f.email.focus();
		return false;
	}
	if (isBlank(f.friendForename.value)) {
		alert("You must enter your friend's forename");
		f.friendForename.focus();
		return false;
	}
	if (isBlank(f.friendEmail.value)) {
		alert("You must enter your friend's email");
		f.friendEmail.focus();
		return false;
	}
	if (!isEmail(f.friendEmail.value)) {
		alert("You have supplied an invalid email address for your friend!");
		f.friendEmail.focus();
		return false;
	}
	return true
}