Have any browsers implemented the DOM3 EventListenerList?
The answer was "no" back in March 2010:
Browser EventListenerList Implementation
I'm wondering if there has been any progress since then.
If the answer's still "no" ... any indication of when any browser might support it?
Answer
For those looking for a practical solution, see: How to find event listeners on a DOM node when debugging or from the JavaScript code?
EventListenerList was in some old draft of DOM 3 Events and was long removed from the spec. As far as I know, at least Gecko still doesn't have anything like this for regular web pages, although it now has an API for privileged code (extensions) to enumerate listeners (see https://bugzilla.mozilla.org/show_bug.cgi?id=570678#c0).
I looked through the W3C mailing lists, and there were a few discussions on this topic, but apparently no use-cases were found to justify the feature. This is the most recent message I could find:
[...] what is the motivation for adding this functionality at all? Previously, the working group resolved to remove the related but less powerful hasEventListenerNS method for lack of a use case, and because there are potential security issues.
(2001) http://lists.w3.org/Archives/Public/w3c-wai-ua/2001OctDec/thread.html#msg89 has some discussion from way back when the EventListenerList was considered.
(2006) http://lists.w3.org/Archives/Public/www-archive/2006Mar/0032.html asks a question to the author of quirksmode who seems to be responsible for the DOM3 EventListenerList myth about the use cases of such a feature; the archives do not list a reply.
(2008) another discussion: http://lists.w3.org/Archives/Public/public-webapi/2008Apr/thread.html#msg66
Note: Commenting on my post is not a good way to provide feedback for the browser vendors and standards organizations. I'm not affiliated with either group, and I doubt they will see or act on the comments here..