function validate () {
	var no_errors = true;
	var future_value = "";
	var future_group = document.getElementById("feedback_form").future;
	for (var i = 0; i < future_group.length; i++) {
		if (future_group[i].checked) {
			future_value = future_group[i].value;
		}
	}
	if (document.getElementById("first_name").value == "") {
		no_errors = false;
		alert("Please enter your first name.");
		document.getElementById("first_name").focus();
	}
	else if (document.getElementById("last_name").value == "") {
		no_errors = false;
		alert("Please enter your last name.");
		document.getElementById("last_name").focus();
	}
	else if (document.getElementById("email").value == "") {
		no_errors = false;
		alert("Please enter your e-mail.");
		document.getElementById("email").focus();
	}
	else if (future_value == "") {
		no_errors = false;
		alert("Please select whether you want to participate in future surveys.");
	}
	return no_errors;
}

function validateLink () {
	if (validate()) {
		document.getElementById("feedback_form").submit();
	}
}