JSFiddle - React, Tailwind, and code Playground

HTML

<select id="select">
    <option value="foo">foo</option>
    <option value="bar">bar</option>
    <option value="baz">baz</option>
</select>

JavaScript

var index, option,
    el = document.getElementById("select");

el.value = "bar";
log( "existent", el );

el.value = "qux";
log( "nonexistent", el );

function log( label, el ) {
    var index = el.selectedIndex,
        option = el.options[ index ];
    console.log( label, {
        "select value": el.value,
        selectedIndex: index,
        "option value": option && option.value
    });
}