JSFiddle - React, Tailwind, and code Playground

HTML

<select id="cars" onchange="record_select()">
    <option value=""></option>
    <option value="volvo">Volvo</option>
    <option value="saab">Saab</option>
    <option value="mercedes">Mercedes</option>
    <option value="audi">Audi</option>
</select>
<br>
<textarea id="comments" style="width: 400px; height: 50px;"></textarea>
<br>
<input type="button" value="change" onclick="change_select()">

JavaScript

function record_select() {
    var x = document.getElementById('comments').value
    var y = document.getElementById('cars').value
    if (y) {
        if (x) {
            document.getElementById('comments').value = document.getElementById('cars').value + ' was selected\n\n' + x
        } else {
            document.getElementById('comments').value = document.getElementById('cars').value + ' was selected'
        }
    }
}

function change_select() {

    document.getElementById('cars').value = 'audi'
    document.getElementById('cars').onchange();

}