A terse gist

markup.html

<form id="placeholder_test">
	<input name="test" type="text" placeholder="Placeholder Text" />
	<button type="submit">Submit</button>
</form>

<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery-placeholder/2.0.7/jquery.placeholder.min.js"></script>

script.js

/* See if fake placeholders 'stick' in some browsers */

$(function(){
  
	$('input').placeholder();
  
  $('#placeholder_test').on( 'submit', function( e ){
    e.preventDefault();
    alert( $(this).serialize() );
  });
  
});