did it work in previous versions? event detection is hard. :(

I have no idea. I just tried it today.

Also

document.implementation.hasFeature('Events.textInput', '')

returns false even though the event is supported.

hasFeature has always been notoriously unreliable as far as I know, so I wouldn't even go there... :)

From what I can see, "textInput" is one of those synthetic events which has no corresponding content attribute (so you can't just <input_element>.onTextInput = function(){ ... }, and you can't check for presence of that property/method). It also doesn't fire when text is input by setting element's "value" attribute (at least in Chrome).

This is bad.

Two (also bad) options I see are:

1. Assume that textInput is supported when global TextEvent object is present. This is unreliable, but it could work.

2. Try to insert element into a document, attach textInput event handler, generate event on an element that would cause element value to change, check if event fired.

Looks like textinput is in flux. http://lists.w3.org/Archives/Public/www-dom/2010OctDec/0098.html

Dunno how we can handle this.

fwiw, the spec: http://www.w3.org/TR/DOM-Level-3-Events/#event-type-textinput