Mailto action in a form?

Can somebody help me please,

I after the simplest solution possible for this.

I'm creating a 'catalogue' style website that purely just information driven so there's nothing too complicated about it yet.

I have used a form on the 'contactus' section of this site with 2 text boxes, name & email address and a text area for the comment field. I've used method="post" action="mailto:..." and that's perfectly acceptable except that after the email has been sent from the default email package the fields are stil populated with text. What I would like to happen is for the email to send and for another htm to open in it's place so that I can display a sort of 'thank you for your comment' message.

I'm aware that forms can only have one action, so perhaps this is a question for the JavaScript people and I'll probably post this thread in that forum too, but I'm after the simplest method of doing this without venturing into server side procedures. The site is in pre production and is stored locally on my machine for now so I have nothing I can test it with server side anyway.

So in conclusion, all I am trying to achieve is when the user clicks the submit button, the result will be the mailto function immediately followed by the opening of a different htm file.

Many many thanks to anyone that can help me.

Maybe add an onclick=nextscreen()

The site is in pre production and is stored locally on my machine for now so I have nothing I can test it with server side anyway.
You could use EasyPHP or XAMPP. :) I find EasyPHP the best though because it is so simple and it works, but choose v. 1.8 because 2.0 doesn't work properly yet.

Thanks very much for that, using a combination of this and the answer I got from the JavaScript guys I achieved what I needed to do.