Other Functions

Here are a few other helpful function that aren't related to the previous sections.

A temporary storage mechanism for individual values.
Display a "CAPTCHA" in your form to help fight spam.
Deletes old, unwanted, unfinalized submissions in the database.
A handy function to check to see if a submission is unique or not. The "uniqueness" can be based on whatever criteria you want - email address, email address and password, user name, etc.
This is used internally to start sessions. Generally you won't need to call this directly.
This displays an appropriate error message if the user fails to enter the CAPTCHA properly.