UNDERSTANDING OBSOLETE HTML TAGS AND ATTRIBUTES

According to WHATWG, HTML5 must redefine how some legacy HTML tags are being used — especially the tags that apply cosmetic alterations and are better suited as CSS definitions. However, rather than deprecate these HTML tags, WHATWG and W3C have decided instead to flag them as obsolete.

The difference between these two is that obsolete tags are still required by web browsers to be supported, but web developers — people like you — are now required not to use them! In other words, if you use any of these obsolete tags in your HTML5 website, HTML5 Validator tools will mildly complain, but HTML5 web browsers will happily comply.

Obsolete Tag(s) Replacement
<acronym> Use the <abbr> tag.
<applet> ...

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