<input name="browser" list="browsers" /><br />
<datalist id="browsers">
    <optgroup label="Microsoft">
        <option value="ie">Internet Explorer</option>
        <option value="edge">Edge</option>
    </optgroup>
    <optgroup label="W3C">
        <option value="firefox">Mozilla Firefox</option>
        <option value="safari">Apple Safari</option>
        <option value="chrome">Google Chrome</option>
        <option value="opera">Opera</option>
    </optgroup>
</datalist>