I created a signup form in CC and added it to my site. When a user successfully subscribes, I need it to redirect them to another page on my site. I found this page:
var postURL = 'https://visitor2.constantcontact.com/api/signup';
url = 'http://mysite.com/success.htm';
Adding the redirect is very easy. Just locate this line of code and add in your own website to the value="" section.
<input data-id="url:input" type="hidden" name="url" value="">