Even though throwing sweets
at children seems a fine idea, I think it is supposed to be
to children. Even this seems to be disappearing under a mountain of health and safety paranoia ("choking hazard").
For the benefit of those not part of the British Empire, the Wikipedia entry above gives a pretty good snapshot of pantomime, especially if you skip over the opening "History" section, which doesn't really relate to what happens nowadays.
There is an amazing site dedicated to all things panto at [
www.its-behind-you.com]