JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" integrity="sha384-1q8mTJOASx8j1Au+a5WDVnPi2lkFfwwEAa8hDDdjZlpLegxhjVME1fgjWPGmkzs7" crossorigin="anonymous">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap-theme.min.css" integrity="sha384-fLW2N01lMqjakBkx3l/M9EahuwpSfeNvV63J5ezn3uZzapT0u7EYsXMjQV+0En5r" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-1.9.1.min.js"   integrity="sha256-wS9gmOZBqsqWxgIVgA8Y9WcQOa7PgSIX+rPA0VL2rbQ="   crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js" integrity="sha384-0mSbJDEHialfmuBBQP6A4Qrprq5OVfW37PRR3j5ELqxss1yVqOtnepnHVP9aJ7xS" crossorigin="anonymous"></script>

<div class="container">
	<h1>Contact Us</h1>
</div>
<div class="container center_div">
  <form id="frmContact" action="contactus.php" method="post">
  	<div class="row">
			<fieldset class="form-group">
  				<label for="Forename">Forename</label>
	  			<input type="text" class="form-control" id="forename" placeholder="Forename">
			</fieldset>
    </div>
  	<div class="row">
			<fieldset class="form-group">
		  		<label for="Surname">Surname</label>
			  	<input type="text" class="form-control" id="surname" placeholder="Surname">
			</fieldset>
    </div>
  	<div class="row">
			<fieldset class="form-group">
				  <label for="Contact Us">Contact Us</label>
			  	<input type="text" class="form-control" id="comments" placeholder="Comments">
			</fieldset>
   </div>
   <div class="row">
     <div class="col-xs-8">&nbsp;</div>
     <div class="col-xs-4">
				<button id="btnSubmit" type="button" class="btn btn-success">Submit</button>
     </div>
   </div>
   </form>
</div>

CSS

form{width:500px;}
input.form-control{width:200px;}

JavaScript

$(function(){

	$('#btnSubmit').click(function(){
		alert('bonk');
		var forename = $("#forename").val();
		var surname = $("#surname").val();
		var comments = $("#comments").val();

		if(forename == null || forename == ""){
			alert("Forename is empty");
			return false;
		}
		else if(surname == null || surname == ""){
			alert("Surname is empty");
			return false;
		}
		else if(comments == null || comments == ""){
			alert("Comments is empty");
			return false;
		}
		$('#frmContact').submit();
	});//END #btnSubmit.click

}); //END document.ready