What is doctype html?

Related questions

1. What is doctype declaration in html5?
2. Is HTML 5 case sensitive?
3. Is doctype html important?
4. Why doctype is used in XML?
5. Is html5 compatible with older browsers?
6. What is doctype is it necessary to use in html5?
7. What is doctype XML?
8. How can we create doctype in html5?
9. What DTD means?
10. How do you know which HTML version I am using?

Tags

1. #definition
2. #should
3. #declaration
4. #document
5. #written
6. #markup
7. #doctype
8. #thing
9. #instruction
10. #refers
11. #version
12. #about
13. #before
14. #language
15. #browser
16. #first