JSFiddle - React, Tailwind, and code Playground

HTML

<form action="javascript:$('#display').text($('#address').val())" id="urlForm">
 <input id="address" type="text" />
 <button type="submit">Submit</button>
</form>
<div id="display"></div>

JavaScript

$(document).ready(function() {
 $('#urlForm').submit(function() {
  var url = $('#address');
  if(url.val().match(/^http:\/\//) == null) {
   url.val("http://" + url.val());
  }
 });
});