JSFiddle - React, Tailwind, and code Playground

HTML

<form action="demo_post_enctype.asp"
method="post" enctype="multipart/form-data">
<select id="test">
 <option value="1">Test One</option>
 <option value="2">Test Two</option>
</select>
</form>

JavaScript

function getSelectedText(elementId) {
    var elt = document.getElementById(elementId);

    if (elt.selectedIndex == -1)
        return null;

    return elt.options[elt.selectedIndex].text;
}

$(function() {
    $('#test').change(function() {
        var text = getSelectedText('test');
        alert(text);
    });
});