function checkform(nForm, requiredPrefix) {
	for (var i = 0; i < nForm.elements.length; i++) {
		if (nForm.elements[i].name.substring(0,1) == "_" && nForm.elements[i].value == "") {
			alert(requiredPrefix + nForm.elements[i].id);
			nForm.elements[i].focus();
			return false;
		}
	}
	return true;
}