Why is doctype needed?

Related questions

1. What are the limitations of DTD?
2. Is doctype declaration necessary?
3. What happens if you dont use doctype?
4. What is the meaning of <! Doctype html?
5. What does a doctype do?
6. What happens if doctype is not specified?
7. What is DTD in xhtml?
8. Why is doctype used?
9. Is doctype mandatory?
10. What if we dont use doctype in HTML?

Tags

1. #document
2. #standards
3. #pages
4. #before
5. #specification
6. #according
7. #requires
8. #ensure
9. #displayed
10. #doctype
11. #declaration
12. #elements
13. #other
14. #every
15. #intended
16. #appears