JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
<form id="registerForm">
  <input type="text" pattern="[A-Za-z]{1,20}" placeholder="First Name" name="guestFName" title="Up to 20 alphabetical characters" required>
  <input type="text" pattern="[A-Za-z]{1,20}" placeholder="Last Name" name="guestLName" title="Up to 20 alphabetical characters" required>
  <input type="email" placeholder="Email" name="guestEmail" title="Must be a valid email address" required>
  <input type="text" pattern="08[36579]-\d{7}" placeholder="Phone Number" name="guestPhone" title="Must be an irish mobile number of format 08?-7 digits" required>
  <input type="password" pattern="(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{8,20}" placeholder="Password" name="guestPassword" title="Must be 8 or more characters long and contain at least one number and one uppercase letter" required>
  <br>
  <button id="myButton">Register</button>
</form>

JavaScript

$(function() {

  $("#registerForm").submit(function(e) {
    e.stopPropagation();
    e.preventDefault();
    
    $.ajax({
        url: "https://httpbin.org/post",
        data: $('#registerForm').serialize(),
        type: 'POST'
      })
      .done(function(response) {
        console.log(response);
        //var result = JSON.parse(response);
      });
  });

});