// form validation of email address
function validateForm(f, fields) {
	var error = '';
	for (var i = 0; i < fields.length; i++) {
		eval("var field = f."+fields[i]+";");
		if (field.value.length == 0) {
			error += fields[i] + "\n";
		}
	}
	if (error.length > 0) {
		alert("Sorry this form can't be submitted because the following fields are incomplete:\n" + error);
		return false;
	}
	return true;
}