I use the bravenet email form (pro user). I want to add coding for certain questions that visitors must answer. Can someone help with this?

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go to your maintenance area for your form and work with it.

Then save and place the full coding on your page for the form and it should work.

Their are different types of forms you can use just work to get one you like with questions you want.

I think our hypephenated friend is confusing the various services. For an email form you will need to write your own custom javascript to validate the content.

The link from my site uses a different forms service but uses javascript to validate entries. A little time with a good search engine should find you a few free validation scripts that you can adapt to your requirements