JSFiddle - React, Tailwind, and code Playground

HTML

<div class="upage" id="id01">
 <div class="main" id="id02">
   <div class="main2" id="id03">
       <input type="text">
   </div>   
 </div>
</div>

JavaScript

$('input').on('focus', function(){
    var id = $(this).closest('.upage').attr('id');
   this.value = id;
});