Contact form "loading" GIF

Hello,

I’m using the contact forms on different pages on my site. Once a visitor fills out the form and click “Send”, the “Send” button disappears and after a few seconds appears a message like “Thank you for the email.” The problem is that the visitor may think the contact form is not working because there’s no ןimmediate response that tells him that the form is sending, such as loading icon. Is there a possibility that when the form is loading a loading icon ( Like GIF) will appears so the visitor know that the form is loading and there’s nothing wrong with it?

link to my website: http://leverate.com/contact/

Thanks for your help!

Omer