function is_valid_computer_id(cid){
	var bang_expression = /^([0-9]{1,4})\s([0-9]{1,4})\s([0-9]{1,4})\s([0-9]{1,4})$/;
	var result = bang_expression.test(cid);
	if (!result) {
		alert ('Invalid computer ID: must be 4 space-separated 1-4 digit numbers.');
		return false;
	}
	return true;
}