`querySelector` cannot resolve selectors with escaped IDs

For example, as a CSS selector, ID as "0foo.000" requires escape the first "0" and "." at least. Current browsers also have CSS.escape(str) builtin for escaping any IDs.

But the current jsdom (9.4.0) cannot resolve the ID above. the code as:

"use strict";

const jsdom = require("jsdom");
const document = jsdom.jsdom();

//(same codes on web console and nodejs)
const elems = document.createElement("div");
const a = document.createElement("span");
a.id = "0foo.000";
elems.appendChild(a);

//fail with jsdom but pass on browsers
console.assert(elems.querySelector("#\\30 foo\\.000") === a);

[P0oOOOo0YA]

Doing jest dom manipulation test with jsdom as test environment, found out CSS is not defined. Seems that it is not implemented.

[Sebmaster]

Just tested this manually and since we already have #1627 open for tests I guess we don’t need this anymore.