I have a dropdown menu with different option groups. If someone selects an option, how can I check which optgroup it belongs to? For example if 'ferrari' were selected, how would you determine which optgroup it belongs to?

Feel free to use jQuery or raw javascript.

<select name="testSelect">
   <optgroup label="fruits">
      <option value="apples">Apples</option>
      <option value="oranges">Oranges</option>
      <option value="pears">Pears</option>
   </optgroup>
   <optgroup label="cars">
      <option value="ford">ford</option>
      <option value="toyota">toyota</option>
      <option value="ferrari">ferrari</option>
   </optgroup>
</select>