Question: Are HTML 5 Tags Case Sensitive?
When you write XHTML, you must write all standard tags in lowercase because XHTML is case sensitive. This means that <HTML> is a different tag than <html> in XHTML.
Answer:
HTML 5, unlike XHTML, is not case-sensitive. This means that <HTML> and <html> and <HtMl> are all the same tag in HTML 5.
Convention in HTML 5 is to Use Lowercase
While it is valid to write tags using any case you prefer when writing HTML 5, the convention is to use all lowercase for tags and attributes. This ensures that if an HTML 5 document is one day converted to XHTML, there will be less difficulty for the developers. Plus lowercase letters are easier to read than uppercase letters, and most HTML editors insert tags as lowercase by default.
