datalist-polyfill
https://github.com/mfranzke/datalist-polypill
HTML
<input type="text" list="elements" name="elements">
<datalist id="elements">
<select>
<option value="a">a</option>
<option value="b">b</option>
<option value="c">c</option>
<option value="d">d</option>
<option value="e">e</option>
</select>
</datalist>