JSFiddle - React, Tailwind, and code Playground

HTML

<input type='text' id='pageName'  name='PageName' class='form-control pageName'>
<p class="NotAllowed" id='NotAllowed'></p>

JavaScript

$("#pageName").keyup(function() {
    $.ajax({
      type: "POST",
      //async: false,
      url: "/echo/html",
      data: {
        'html': jQuery(this).val()
      },
      cache: false,
      success: function(response) {
        $("#NotAllowed").text(response);
        //$('#loader_image').hide();
      }
    });
  });