These changes are consistent with html. Current browsers do not use XHTML; however, it is possible to write XHTML that is compatible with HTML, and will work on existing HTML-based browsers. [W3C recommendation. Accessed 26 January 2000.] Meta search tags [All info in brackets is explanatory and not part of the HTML code.]:
Most HTML tags come in pairs, an opening and closing set. The text to be formatted by the tags is written between the pair. It is essential for both tags to be present for the document to work correctly. All tags are enclosed in left and right angle brackets and (>). Closing tags are preceded by a backslash (/). The tags are not case sensitive Beginner Concepts: How CSS Selectors Work | CSS-Tricks Feb 24, 2018 Meta Tags - How Internet Search Engines Work | HowStuffWorks
The declaration must be the very first thing in your HTML document, before the tag. The declaration is not an HTML tag; it is an instruction to the web browser about what version of HTML the page is written in. In HTML 4.01, the declaration refers to a DTD, because HTML 4.01 was based on SGML.
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Jan 01, 2020 List of All HTML Tags - Tech Spirited