646687 - In addEventListener useCapture is not optional, but should default to false

Status: VERIFIED DUPLICATE of bug 613634

(Core :: DOM: Events, defect)

Description

[michael]

User-Agent:       Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:2.0) Gecko/20100101 Firefox/4.0
Build Identifier: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:2.0) Gecko/20100101 Firefox/4.0

From my understanding of javascript standards, the useCapture argument to addEventListener should be optional, that is it should default to false.

e.g.
window.addEventListener("load", window_load);

Should be the same as:
window.addEventListener("load", window_load, false);

This works in WebKit browsers, but not Firefox 4.0, but it also fails silently.

Reproducible: Always

Steps to Reproduce:
Call the addEventListener method leaving out the optional useCapture argument. 
Actual Results:  
The event will never be added and the script will not break at that point.


Expected Results:  
The software should have assigned the event with useCapture set to false, or less ideally thrown an exception.

Comment 2

[Boris Zbarsky [:bzbarsky]]

Verified.  Note that according to current standards this argument is not optional, though there are proposals to change the standards to make it optional.

Comment 3

[:Ms2ger (he/him; ⌚ UTC+1/+2)]

(Depends on what you mean by current standards, I suppose. Both DOM Core <http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#interface-eventtarget> and DOM 3 Events <http://dev.w3.org/2006/webapi/DOM-Level-3-Events/html/DOM3-Events.html#interface-EventTarget> make it optional.)

Comment 4

[Olli Pettay [:smaug][[e-mail]]]

Both DOM 3 Events and DOM Core are drafts, and they will change, as you know ;)

Comment 5

[Boris Zbarsky [:bzbarsky]]

Ms2ger, neither of those is close to being a REC (or even LC), as you well know.