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"DOCTYPE" vs "doctype"

I'm just starting out and currently in the beginner HTML course. Nick uses <!doctype html> instead of <!DOCTYPE html>. My text editor didn't like that. Isn't the lowercase doctype incorrect?

1 Answer

Sri Kadimisetty
Sri Kadimisetty
9,770 Points

No it's cool to have <!DOCTYPE ... be lower case in HTML. :)

In fact, tags are case insensitive in the HTML spec although the DOCTYPE keeps getting referred to in the upper case through the specs; although that might be because of HTML's associations with XML which requires the doctype tag to be in uppercase. Personally I would choose the lowercase because of HTML Polyglot Markup (which aims for compatibility between HTML & XHTML) specs require using lower case doctypes.

My guess for your text editor acting that way is it's syntax analysis engine might have been initially written to parse XML.