Living standard: Add document.implementation.createHTMLDocument()

[fhemberger]

This adds support for document.implementation.createHTMLDocument()to the living standard.
It took some time to get my head around the jsdom code, hopefully I did it right. ;)

[domenic]

Hi! This is awesome work.

I'd really like to get the web-platform-tests running directly. Is there a reason why you think that's not possible?

[fhemberger]

It only differs from the original tests in one point: In the living standard, localName is also returned for nodes without namespace (i.e. lowercase version of nodeName value), which goes against the DOM Level 1(?) specs. I wasn't sure how to implement this only being available in the living standard version, so I left it out for now as it's only a minor issue.

[domenic]

Well, anything in DOM level 1 is just wrong, so let's definitely fix that, even if jsdom has tests to the contrary.

[fhemberger]

Here you go. localName is now returned for type ELEMENT_NODE (doesn't make much sense to me for the other types). Tests are passing.

[domenic]

Awesome! Can we run the web-platform-tests directly now? Per https://github.com/tmpvar/jsdom/blob/master/Contributing.md#writing-or-importing-tests ?

[fhemberger]

Unfortunately not yet:

• Creating a doctype with
  document.doctype = this.createDocumentType("html"); should (according to the w3c test) result in publicId and systemId to be empty strings (returns "undefined" as string instead).
• Metadata is still missing, I didn't know where to get it.

As this is my first PR to this project (with a complex codebase), I tried to be cautious not to break anything. If you can point me to the right direction, I'll see to get the w3c test passing as well in the next days.

[Sebmaster]

Fixing createDocumentType should be as simple as replacing level2/core.js by

doctype._publicId = publicId ? String(publicId) : "";
doctype._systemId = systemId ? String(systemId) : "";

[fhemberger]

Ok, added the w3c test, one test is still failing, regarding character escaping on href attributes when using createElement.

[domenic]

OK sweet, we'll try to fix that for you and merge this asap :)

[fhemberger]

Cool, thanks!

[domenic]

Element, not Node

[fhemberger]

Ah, ok. Just took it from https://github.com/tmpvar/jsdom/blob/master/lib/jsdom/level2/core.js#L153

[domenic]

Thanks so much for your awesome work. Merged as 5fc594d and d84dab8, and I'll clean up a few more things and do a release shortly.

Thanks for bearing with us in an area of the code that's messier than usual due to the historical levels stuff.

[fhemberger]

You're welcome! Thanks for all the work with jsdom and your great help with the PR. Not many maintainers take the time to review contributions in such detail.