Capital letters for the word 'doctype' are not mandatory for HTML, only for XHTML. https://html.spec.whatwg.org/multipage/syntax.html#the-doctype https://html.

Capital letters for the word 'doctype' are not mandatory for HTML, only for XHTML. https://html.spec.whatwg.org/multipage/syntax.html#the-doctype https://html.spec.whatwg.org/multipage/syntax.html#the-docty...