Help:Bad title

Some page titles are defined as bad for various reasons. You can't create pages with these titles.

For details of what constitutes a bad title, see regex section or Title.php .

For reference here is an example of a horrible, but valid title:

• Some¬`!"£$^&*()_+-=~?/.,;:'@

Things you can't use in titles:

• The following standard CGI chars are not good:
  • https://www.mediawiki.org/wiki/Some%s — Very bad!

• The following standard wiki syntax seems to work:
  • https://www.mediawiki.org/wiki/Some%sSome[s — gets trimmed
  • https://www.mediawiki.org/wiki/Some%sSome]s — gets trimmed
  • https://www.mediawiki.org/wiki/Some%sSome{s — bad
  • https://www.mediawiki.org/wiki/Some%sSome}s — bad

• and some just don't work:
  • https://www.mediawiki.org/wiki/Some%sSome#s — gets trimmed

• and some HTML like constructs are very bad, and can't be shown here because they break page formatting:
  • https://www.mediawiki.org/wiki/Some%sSome<s — bad
  • https://www.mediawiki.org/wiki/Some%sSome>s — bad

These vary according to the version number of the software:

• 400 (Bad Request) for v1.19.1 and above
• 200 (OK) for v1.16.4 and earlier

# Matching titles will be held as illegal.
$rxTc = '/' .
	# Any character not allowed is forbidden.
	'[^' . self::legalChars() . ']' .
	# URL percent encoding sequences interfere with the ability to round-trip titles, you can't link to them consistently.
	'|%[0-9A-Fa-f]{2}' .
	# XML/HTML character references produce similar issues.
	'|&[A-Za-z0-9\x80-\xff]+;' .
	'|&#[0-9]+;' .
	'|&#x[0-9A-Fa-f]+;' .
	'/S';

• $wgLegalTitleChars
• Title.php

• Help