DOM event detection

After a brief correspondence with Robin Berjon he suggested I post this
suggestion here.

After having problems with detecting support for the HTML5 'input' event (
http://goo.gl/XNSg5 http://goo.gl/rAa5f) I started wondering if there was a
DOM specification for detecting support for DOM events in browsers.

After a brief email correspondence with Robin Berjon, and looking around a
bit myself, it appears that there is no specific mention of this in the
current HTML5 or DOM specifications. There is some mention of DOM events
being exposed as methods (http://goo.gl/TYm2k) but this may not necessarily
apply to all DOM elements.

Therefore, I'd like to suggest that we try to come up with a standard way of
suggesting that support for DOM elements be exposed, to enable developers to
tell which events are supported.

One method that works in Webkit and Gecko for many methods, although I don't
think it's in any W3C specification, is to include methods for each event
them in the "Event" object, e.g.:

'CLICK' in Event; // true
'CHANGE' in Event; // true
'INPUT' in Event; // false

Does that seem like a reasonable method of DOM event support detection?
Could it be included as a recommendation in the specification somewhere?

Cheers,
Robin.