JSFiddle - React, Tailwind, and code Playground

HTML

<div id="hideMsg">
The entry you posted not valid.
This Box will Close In <span>2</span> Seconds
</div>

JavaScript

var sec = 2
var timer = setInterval(function() { 
   $('#hideMsg span').text(sec--);
   if (sec == -1) {
      $('#hideMsg').fadeOut('fast');
      clearInterval(timer);
   } 
}, 1000);