JSFiddle - React, Tailwind, and code Playground

HTML

<form id="myform" action="javascript:alert('envoyé')" onsubmit="alert(this.id)" >
    <input type="hidden" id="bar" value="coucou" />
    <input type="submit" id="valid" value="valid" />
</form>
<input type="button" id="clone" value="clone" />
<div id="output"></div>

JavaScript

var inc=0;
$("#clone").click( function(){
  $newform = $('#myform').clone(true).attr("id","myform"+ ++inc);
      $('#newform :hidden').attr('id',"bar"+inc);
      $('#newform :submit').attr('id',"valid"+inc);
  $("#output").append( $newform );
    
      })