basefont element

basefont is obsolete and does nothing: only old Internet Explorer applied it, and the HTML Standard renders it as display:none. Set the font in CSS.

Avoid
Deprecated

Severity: DeprecatedFormally obsolete, but inert.
Basis: Obsoleted by the specA standard defined it, then removed it.
Detectable: YesMatched exactly. Autofixable when the rule carries a fix.
Matches: basefontElement rule, anywhere in the document.
Fix: None — reports only
Impacts: Maintainability
Related: element/font, element/acronym

<basefont size="4" color="navy" face="Verdana"> was meant to set the default font for a whole document in one place, so every later <font size="+1"> would count from it. Internet Explorer honoured it. Netscape and its successors never did. Today it is a line of markup that looks as if it sets the page’s type, and sets nothing.

Why avoid

It is obsolete and non-conforming. The HTML Standard lists basefont among the elements that “are entirely obsolete, and must not be used by authors”, alongside font, center, big and tt, with the instruction “Use appropriate elements or CSS instead.”

It has no effect. The Standard’s rendering rules put basefont in the list of elements styled display: none, and define nothing for its size, color or face attributes. Firefox never applied it at all: Mozilla’s bug for it, “deprecated <basefont> element not supported”, was closed WONTFIX, with Ian Hickson’s advice that “Authors should not use deprecated elements, certainly not in new documents. Use CSS instead.”

That makes it misleading rather than harmless. Anyone maintaining the page reads it as the source of the site’s base font size and colour, keeps it through redesigns, and wonders why changing it does nothing. The real styling lives somewhere else, and this line only hides that.

Use instead

Set the document’s font once, in CSS:

body {
  font-family: system-ui, sans-serif;
  font-size: 1rem;
  color: #222;
}

Relative sizes such as rem and em then count from that, which is what basefont was trying to offer.

Detectability

Fully detectable by tag name, in <head> or <body>: the parser handles basefont like <link> wherever it appears, as a void element with no end tag.

There is no autofix. Deleting it would change nothing a reader sees, since it does nothing, but whether to remove it is left to the author.

Resources

HTML Standard — Non-conforming features — basefont is entirely obsolete: “Use appropriate elements or CSS instead.”
HTML Standard — Rendering: hidden elements — basefont is display: none, with no presentational hints for its attributes.
HTML Standard — Parsing: the “in head” insertion mode — basefont start tags are processed with base, bgsound and link.
Mozilla Bugzilla 3875 — deprecated <basefont> element not supported — resolved WONTFIX: Firefox never applied it.

legacy
head
style

This page is generated from content/rules/element/basefont.md, the same file the linter is built from. Think the rule is wrong, or that browsers moved on? Say so — that is the most useful issue you can file.