CODE EXAMPLE FOR HTML

nested select option in html

<select>
  <optgroup label="1">
     <option>Nested Option 1</option>
     <option>Nested Option 2</option>
  </optgroup>
  
  <optgroup label="2">
     <option>Nested Option 1</option>
     <option>Nested Option 2</option>
  </optgroup>
</select>