358091 - captureEvents(), releaseEvents(): False deprecation warning for scripts based on object-detection

Status: RESOLVED INVALID

(Core :: DOM: Events, defect)

Description

[Walter Zorn]

User-Agent:       Opera/9.02 (Windows NT 5.1; U; en)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1) Gecko/20061010 Firefox/2.0

Presently, the JS-console-warning "Use of captureEvents() is deprecated" without reason is displayed for scripts based on object detection rather than on browser detection. That is, even if a script doesn't rely on these functions, but rather checks for their existence before calling them.

This is annoying for JS developers who receive a lot of false alarms by users, though their scripts aren't really broken (yes, I'm a victim of this :)). And it is disturbing for less-experienced JS developers.


Reproducible: Always

Steps to Reproduce:
JavaScript:

g_oldMoveFunc = document.onmousemove; // Store reference to previous handler
if(document.captureEvents)
    document.captureEvents(Event.MOUSEMOVE);
document.onmousemove = someMoveFunc;

Actual Results:  
A false "Use of captureEvents() is deprecated" warning is written to the JS console.

Expected Results:  
The warning should not appear for the JS lines above. Reason: If a browser doesn't support captureEvents(), line 2 will evaluate to false, and the browser cannot enter line 3.

Nothing. Just ignore line 3.

Comment 1

[Walter Zorn]

*** Bug 358092 has been marked as a duplicate of this bug. ***

Comment 2

[Alex Vincent [:WeirdAl]]

This refers to a pre-DOM Level 2 Events specification for how Gecko handled events.  These methods really are deprecated, but apparently still supported.  Websites using them should be evangelized into using the proper DOM 2 Events methods (addEventListener), as these methods may actually be *removed* altogether in the future.

Recommend INVALID.

Comment 3

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

IMO, the warning should happen since captureEvents *is* deprecated, 
and the method call doesn't do *anything* in trunk builds.
(It still does do "something" in 1.8)
captureEvents was implemented in Netscape 4 and that browser sure is
pretty obsolete.

Comment 4

[Günter Essers]

Attachment: screenshot to illustrate bug 330494-message when using oracle metalink

Hi,
the error occurs if using firefox 2.0.0.7, and occurs not if using IE6. This issue prevents users from login to oracle metalink.
Regards
Günter

Comment 5

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

Sorry, but this is invalid.
on 2.x builds captureEvents is (sort of) supported, the message is just a warning that web app is using *deprecated* method. Note, the message doesn't say *obsolete* method or anything like that.

And this sure doesn't prevent any functionality. If you can't login to
"oracle metalink", the problem is somewhere elsewhere.