Intent to Deprecate and Remove: xml:base

Philip Jägenstedt

unread,

May 13, 2015, 5:24:52 PM5/13/15

to blink-dev, Anne van Kesteren

Primary eng (and PM) emails

Summary

Remove support for xml:base entirely. This will be observable in the Node.baseURI IDL attribute for Elements as well as any code that uses baseURI() internally.

Motivation

xml:base is not part of the current DOM spec, and the spec editor (Anne van Kesteren) filed a bug to remove it from Blink. This is a slight modification of the model, so that only the document has a base URL. A WIP CL shows what can be removed.

Compatibility Risk

Any content that depends on xml:base would resolve against the wrong base URL and thus fail to load some resource. The only test cases we have are for SVG <image>, so perhaps in SVG is the most likely place to find xml:base.

Alternative implementation suggestion for web developers

Use absolute URLs, change the relative URLs, or use <base href="...">.

Usage information from UseCounter

https://www.chromestatus.com/metrics/feature/timeline/popularity/580

This counter was in M40, but has never registered a non-zero value, which ought to mean < 0.0001% every day. The counter is in the only code path where the xml:base attribute is read, so it covers any possible observable behavior of xml:base support.

Entry on chromestatus.com, crbug.com, or MDN

https://crbug.com/341854

Requesting approval to remove too?

Yes, usage is already extremely low.