JSFiddle - React, Tailwind, and code Playground

HTML

<select id="mySelect">
    <option value="" style="display: none;"></option>
    <option value="aaa">AAA</option>
    <option value="bbb">BBB</option>
</select>
<input type="text" />
<div id="Console"></div>

JavaScript

window.onload = function() {
    var oDDL = document.getElementById("mySelect");
    oDDL.selectedIndex = 0;
    oDDL.onchange = function() {
        alert("hello");
    };
};