Bug 33861

Summary:	Document is not notified about event listener changes
Product:	WebKit	Reporter:	Nikolas Zimmermann <zimmermann>
Component:	DOM	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Major	CC:	ap, cdumez, darin, ddkilzer, eric, mjs, staikos, tonikitoo
Priority:	P2
Version:	528+ (Nightly build)
Hardware:	All
OS:	All

Description Nikolas Zimmermann 2010-01-19 13:19:51 PST

Document keeps track wheter a certain event listener is available in the DOM, we only dispatch certain events if document()->hasListenerType(..) returns true.
In Node::addEventListener, we're adding the listener type, but in Node::removeEventListener we're not notifying the Document that something changed.

We need to switch to a counting based tracking scheme, counting how many event listeners are registered for each event type.
This bug can introduce performance problems, when adding a mutation event listener once for ie. <body> and then removing it. We will never stop dispatching mutation events.

Comment 1 Alexey Proskuryakov 2012-08-28 09:45:32 PDT

Does this happen on real web sites? Counting listeners would add a toll on every web site, while benefits seem unlikely to materialize.

Comment 2 Lucas Forschler 2019-02-06 09:02:44 PST

Mass moving XML DOM bugs to the "DOM" Component.