JSFiddle - React, Tailwind, and code Playground

HTML

<select id="aaa">
    <option>0</option>
    <option>1</option>
    <option>2</option>
    <option>3</option>
    <option>4</option>
</select>

<input type="button" id="btn" value="按這個可以觸發select的選取事件嗎">

JavaScript

$("#btn").click(function() {
document.getElementById("aaa").selectedIndex=3;
    
})