Trick-or-treating

Read the first paragraph of this website link about the tradition of ‘trick-or-treating’: http://en.wikipedia.org/wiki/Trick-or-treating and answer the following questions.
1. What do children ask for when they travel from house to house? (Note: the answer is an American word, do you know the British English equivalent?)
2. What question do the children ask?
3. What is usually the ‘trick’?
4. Since when has this tradition been practised in North America?
5. What do homeowners who wish to participate usually do to their houses?
6. In what countries did two traditions similar to trick-or-treating already exist?
7. What were these traditions called?
8. What was different about these to current trick-or-treating traditions?
9. Trick-or-treating has become prevalent in countries outside of America – what do the children ask for in Mexico?