Force New Members to Enter Word Before Posting

[Dave Hawley]

I would like to know how to show a textbox, or something, on the newthread page IF the member has a post count of zero. They must then enter a specific word in that box to be able to post their Thread. The specific word can be hard coded.

I know how to determine their post count, but have no idea how to add a box and ensure the word they enter is correct and if not, prevent posting the thread.

Any help greatly appreciated.