Where we used to have all members of the entire inheritance chain (e.g.
EventTarget) on the interface prototype object of the leaf class (e.g.
HTMLDivElement.prototype === document.createElement("div").__proto), we now put the members of
HTMLElement just on
It turns out that at least one important library, Optimizely, relied on this erroneous behaviour. They quickly fixed it on their side, but it is important that any Web site using their tool upgrade to the latest versions.
null to a method that takes a
DOMString argument will stringify to
"null" instead of the empty string. For example,
element.setAttribute("foo", null) will result in an output like
<div foo="null"> instead of
parseFromBuffer methods of
DOMParser as well as the
serializeToStream method of
XMLSerializer are now deprecated and no longer available on content. Those still work on chrome (or extension code).