JSFiddle - React, Tailwind, and code Playground

HTML

<form>
  <input type="text" id="txtfld" onkeypress="f2()"/> 
  <input type="button" onclick="typeKey()" value=go > 
</form>
<script>

function fire(el,evttype,code) {
   if (document.createEvent) {
     var evt = document.createEvent('HTMLEvents');
     evt.initEvent( evttype, false, false);
    evt.charCode= evt.keyCode = code;
     el.dispatchEvent(evt);
   } else if (document.createEventObject) {
    var evt = document.createEventObject();
    evt.charCode= evt.keyCode = code;
     el.fireEvent('on' + evttype,evt);
   }
}
function typeKey(){
  var el = document.getElementById('txtfld');
      ev = window.event ? window.event : ev; 
      fire( el,'keypress',68);
    
}

function f2(ev){
    var KeyID = (window.event) ? event.charCode : ev.keyCode;
    alert('key pressed '+KeyID);
}

</script>