Trouble combining spry validation form with ajax process script

Can anyone help with this please.
I have an ajax contact form which works fine. I’ve added spry validation to the form but the user is still able to send the form without filling in any data which is not what I want obviously.
The spry validation seems to be being ignored because I have set the ajax event as an onClick on the submit button for the form.

Can anyone tell me how I can get these to work correctly together please?

Any help much appreciated.

Thanks in advance.