Contact form won't disply 'Message sent' on page (HTML5/CSS/jQUERY)

Trying to get this page on: http://ift.tt/1IYj74x

to display a "Congratulations. Your message has been sent successfully" message when you click send on the contact form as it does on: http://ift.tt/1GUYIbS

I've ripped the form identically, it sends me the email yet doesn't update the page with the messsage sent succesfully notice?