Every school has its rules(规定). Here are some school rules in different countries.
Japanese rules
Most Japanese schools ask the students to wear school clothes. In many Japanese schools, if the schools don't know, students can't go to the cinema, leave home in the evening or play computer games.
Different shoes in the USA
In some schools, students must wear indoor(室内的)shoes at school every day. So the students can't fall down(倒下), and they are safe on the floors. Students can't eat gum(口香糖)in school, because it is hard to clean.
No strange hair in the UK
Students can't have strange(奇怪的)hair in some British schools. But the students can have certain hairstyle(发型)in the World Cup years.