[whatwg] Attribute for holding private data for scripting

[Sam Ruby]

On 4/10/07, Simon Pieters <zcorpan at gmail.com> wrote:
>
> Or allow any attribute that starts with "x_" or something (to prevent
> clashing with future revisions of HTML), as private attributes.

Instead of "starts with x_", how about "contains a colon"?

A conformance checker could ensure that there is a corresponding xmlns
declaration that applies here, and possibly even do additional
verification if it recognizes the namespace.

An HTML5 parser would, of course, recover from references to
undeclared namespaces, placing the entire attribute name (including
the prefix and the colon) into the DOM in such situations.