HTML form (ACTION="mailto.... + redirect

Hello and thanks for your help in advance.
I have written some HTML for a event registration form that the user fills in the details and when they click the send button it emails me their details. I would also like it to then go to another page on my site, how can I do this. Thanks.

Here is my code:

Do I have to append the ACTION line to mailto and also redirect?? This needs to be in HTML and not CGI or PHP etc. Thanks.
Thanks