function validate_form() {
	if (document.getElementById("firstname").value == "") {
		alert("Please enter your first name.");
		document.getElementById("firstname").focus();
		return false;
	}

	if (document.getElementById("lastname").value == "") {
		alert("Please enter your last name.");
		document.getElementById("lastname").focus();
		return false;
	}

	if (document.getElementById("email").value == "") {
		alert("Please enter your email address.");
		document.getElementById("email").focus();
		return false;
	}

	var email = document.getElementById("email").value;
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (!filter.test(email)) {
		alert("Your email address does not appear to be valid.  Please check the spelling and try again.");
		document.getElementById("email").focus();
		return false;
	}

	return true;
}