JSFiddle - React, Tailwind, and code Playground

HTML

<input value="default" />
<select>
    <option value="">- select -</option>
    <option value="1">one</option>
    <option value="2">two</option>
</select>

JavaScript

$('input').hide();
$('select').change(function() {
    $('input').val($(this).val());
});

//function toggleVisible() {
//    if($('input').is(':visible')) $('input').hide();
//    else $('input').show();
//    setTimeout(toggleVisible, 3000);
//}
//toggleVisible();