[whatwg] [Selectors4] case-insensitive attribute value matching (in XML)

[Christoph Päper]

Anne van Kesteren:
> I'm still trying to get HTML and browsers to change so that attribute values always match case-sensitively, irrespective of markup language. The current magic attribute list in HTML whose values needs to be matched ASCII case-insensitively is just ugly.

Can’t that be changed to something like the following?

  When an attribute takes as a value
  – a single keyword or
  – a whitespace-separated list of keywords,
  where all valid keywords are defined in this spexcification,
  these keywords are ASCII case-insensitive.
  All other attribute values are case-sensitive.

or just

  All element names, attribute names and attribute value keywords
  defined in this specification are ASCII case-insensitive.
  All other attribute values are case-sensitive.