1 Tests basic web-exposure of Custom Elements
3 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
6 Document.prototype.hasOwnProperty("registerElement")
9 typeof Document.prototype.registerElement
12 document.createElement("x-a") instanceof HTMLUnknownElement
15 document.querySelector(":unresolved")
16 [object HTMLDivElement]
18 span.getAttribute("is")
21 PASS successfullyParsed is true