That's a very tricky question which I currently have no answer for.
This guy from a church asked me if I could "put a survey on their site". Better to quote him:
We were looking for someone who would be able to do some coding to take the information from the survey/assessment that someone takes and show them the results on the following page once they submit the survey/assessment.
Well, after lots of mailing back and forth followed by a skype video call I realized what he meant. And it's nothing Squarespace Forms or Google Forms can do. I think neither survey monkey. So best thing I could tell him is to search for a service that does what he wants and we'd see from there. Also I think the best one I could find after very little research of my own was this: http://woobox.com/quiz