JSFiddle - React, Tailwind, and code Playground
HTML
<input type="text" class="txtbox"></input>
<input type="button" class="btn"></input>
<p class="myp">demo here</p>
CSS
.myp{background:#aaa;}
JavaScript
$('.txtbox').keyup(function(){
var abc = $('.txtbox').val();
$(".myp").text(abc);
});