JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" id="foo" value="1" checked="checked"/>
<div style="display:none;" id="checked-a">
    Some content
</div>

<input type="hidden" id="hdn1" value="yes" />

JavaScript

$("#foo").change(function(){
   
   var ischecked=$(this).is(':checked'); 
    if(ischecked)
    {
         $("#checked-a").fadeIn(200);
    }
    else
    {
        $("#checked-a").fadeOut(200);   
     }
    
});
                 

$(function(){
   
    var ischecked=$("#foo").is(':checked'); 
   if(ischecked)
   {
       $("#checked-a").fadeIn(200);
   } 
    else
    {
        $("#checked-a").fadeOut(200);   
     }
    
});