JSFiddle - React, Tailwind, and code Playground

by Yogesh Gupta

HTML

<script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
<input id="inp">
<button>
My Button
</button>

JavaScript

function block_button(elem, min){
  current=elem.val().length;
  if(current>=min){
  elem.next().css('opacity','1');
  }else{
  elem.next().css('opacity','0.5');
  }
}

$('input').keyup(function(){
   block_button($(this), 4);
});