JSFiddle - React, Tailwind, and code Playground

HTML

<select id='a' style='width:300px' size='5'>
    <option id='a1'>a1</option>
    <option id='a2'>a2</option>
    <option id='a3'>a3</option>
    <option id='a4'>a4</option>
    <option id='a5'>a5</option>
    <option id='a6' value='a6'>a6</option>
</select><br/>
<input type='button' id='btn' value='Add'/>

JavaScript

$(document).ready(function() {
    $('#btn').click(function() {
        var $s = $('#a');
        var optionTop = $s.find('[value="a6"]').offset().top;
        var selectTop = $s.offset().top;
        $s.scrollTop($s.scrollTop() + (optionTop - selectTop));
    });
});