JSFiddle - React, Tailwind, and code Playground

HTML

<select id="s">
    <option>1</option>
    <option>2</option>
</select>
<button >clicky</button>

JavaScript

$(document).ready(function(){
   
    $("button").click(openSelect);
})
function openSelect() {
  
     var element = document.getElementById("s")
       var worked = false;
     if (document.createEvent) { // all browsers
         var e = document.createEvent("MouseEvents");
         e.initMouseEvent("mousedown", true, true, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
                  
 
         worked = element.dispatchEvent(e);
         
     } else if (element.fireEvent) { // ie
         worked = element.fireEvent("onmousedown");
     }

 }