Hopefully quick CAPTCHA question (form submit)

I've got a page with an old form that I'm trying to add a CAPTCHA to.

The original form was set to send to Salesforce (not sure if you know it?) using:

form action="https://www.salesforce.com/servlet/servlet.WebToLead?encoding=UTF-8"

So I've added all the CAPTCHA stuff to the form, but I'm not sure how to get the form to check the CAPTCHA before the page submits?

The page is here:

indextest3.php

And I've attached the file showing how it currently looks.

I tried to spoof it using an insert into DB form, but it didn't seem to work, plus I expect there's a simpler method anyway.

Thanks again.

all form processing must occur on the forms action page

You wont be able to use captcha on this form since it posts to another page that you don't have access to.

Thanks Jason. I has just been trying to think of a way for the form to submit to that same page, check the CAPTCHA, and then redirect if the CAPTCHA passed. But ran in to the problem of being able to do that without the page redirecting when it initially loads.

you would need to add an if statement to check for the form being submitted before redirecting.