<!DOCTYPE html>
<html>
<head>
<title>optgroup Kullanımı</title>
</head>
<body>
<select>
<optgroup disabled label="İsviçre Arabaları">
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
</optgroup>
<optgroup label="Alman Arabaları">
<option value="mercedes">Mercedes</option>
<option value="audi">Audi</option>
</optgroup>
</select>
</body>
</html>