<form action="#">
<dl>
<dt><label for="myenv">あなたのPC環境は?</label></dt>
<dd>
<select id="myenv" name="myenv">
<option value="" selected="selected">▼ひとつ選択してください</option>
<optgroup label="Windows">
<option value="windows95">Windows 95</option>
<option value="windows98">Windows 98</option>
<option value="windows98SE">Windows 98 Secound Edition</option>
<option value="windowsNT">Windows NT</option>
<option value="windowsME">Windows ME</option>
<option value="windows2000">Windows 2000</option>
<option value="windowsXP">Windows XP</option>
<option value="windowsVista">Windows Vista</option>
</optgroup>
<optgroup label="Macintosh">
<option value="puma">Mac OS 10.0 (Puma)</option>
<option value="cheetah">Mac OS X 10.1 (Cheetah)</option>
<option value="jagar">Mac OS X 10.2 (Jaguar)</option>
<option value="panther">Mac OS X 10.3 Panther</option>
<option value="tiger">Mac OS X 10.4 Tiger</option>
<option value="leopard">Mac OS X 10.5 Leopard</option>
<option value="mac_other">それ以外のMac OS</option>
</optgroup>
<option value="other">その他</option>
</select>
</dd>
</dl>
</form>