Closed Bug 939396 Opened 9 years ago Closed 9 years ago

onChange event is not fired on input type range for first time


(Core :: DOM: Core & HTML, defect)

Not set



Tracking Status
firefox26 - wontfix
firefox27 --- fixed
firefox28 --- fixed


(Reporter: tasleem.fahad, Assigned: jwatt)




(4 keywords, Whiteboard: [bugday-20131118][qa-])


(1 file)

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:25.0) Gecko/20100101 Firefox/25.0 (Beta/Release)
Build ID: 20131025151332

Steps to reproduce:

1. Attach an onChange handler on input type range
2. Change the value by clicking (not by dragging)
3. The handler is not called as the event is not fired.
4. Change the value again (second time) 
5. The event gets fired and handler is executed.

Actual results:

onChange is not fired for first time

Expected results:

OnChange should be fired
Severity: normal → major
Priority: -- → P2
Is it bug 890710?

If not, please attach a testcase.

[The Priority part of the Importance field is for the developers only.]
Keywords: testcase-wanted
Priority: P2 → --
Whiteboard: [bugday-20131118]
It is different, I think. I have attached the fiddle URL (

It has always been so, since bug 851090 was fixed.
no event: 2013-03-17-03-09-23-mozilla-central-firefox-22.0a1.en-US.linux-x86_64
bug: 2013-03-18-03-09-47-mozilla-central-firefox-22.0a1.en-US.linux-x86_64
Component: Untriaged → DOM: Core & HTML
Ever confirmed: true
OS: Windows 7 → All
Product: Firefox → Core
Version: 25 Branch → Trunk
Jonas, now that Mounir is gone who gets these bugs?
Flags: needinfo?(jonas)
jwatt might be interested in this stuff.
I implemented <input type=range>, but I don't anticipate getting to this in the few weeks before I go off on PTO.
Jwatt maybe?
Flags: needinfo?(jonas) → needinfo?(jwatt)
Flags: needinfo?(jwatt)
Would this be something you could act as a mentor for, in that case?
Flags: needinfo?(jwatt)
Flags: needinfo?(jwatt)
Whiteboard: [bugday-20131118] → [bugday-20131118][mentor=jwatt][lang=c++]
The reason this is happening is because the code to handle 'focus' events resets the mFocusedValue member, but this happens after the 'click' event has triggered a StartRangeThumbDrag() call that updates the value (and range thumb position). Hence the focus code is unwittingly overwriting mFocusedValue with the value that the range got due to the click, and not leaving it with the value it had just before the click.
Whiteboard: [bugday-20131118][mentor=jwatt][lang=c++] → [bugday-20131118]
Attached patch patchSplinter Review
Assignee: nobody → jwatt
Attachment #8335622 - Flags: review?(bugs)
Am I reading correctly that this has been the case since bug 851090 landed in FF22?  If that's the case and we haven't seen a ton of web breakage because of this, there's no reason to hold a release for this fix.  Please nominate for uplift if low risk and we'll go as high as we can at that time but it's quite late in the FF26 beta cycle and we're throttling down on taking speculative fixes at this point so unless there's something I'm not seeing here in terms of urgency this might only get as high as FF27.
Flags: needinfo?(jwatt)
Keywords: regression
Okay. I don't think this is super high priority, but it does seem a bit bad that script won't get notified of changes caused by a click. I'll nominate after review.
Flags: needinfo?(jwatt)
Attachment #8335622 - Flags: review?(bugs) → review+
Nominate for uplift when ready and we'll see how high up we can lift it safely.
Closed: 9 years ago
Flags: in-testsuite+
Resolution: --- → FIXED
Target Milestone: --- → mozilla28
Comment on attachment 8335622 [details] [diff] [review]

[Approval Request Comment]
Bug caused by (feature/regressing bug #): bug 344618
User impact if declined: script isn't notified of click changes to ranges
Testing completed (on m-c, etc.): been on m-c for a week or so
Risk to taking this patch (and alternatives if risky): pretty low
String or IDL/UUID changes made by this patch: none

Probably not for beta at this point, but I think we should definitely take it on aurora.
Attachment #8335622 - Flags: approval-mozilla-aurora?
Attachment #8335622 - Flags: approval-mozilla-aurora? → approval-mozilla-aurora+
Keywords: checkin-needed
Whiteboard: [bugday-20131118] → [bugday-20131118][needs landing on aurora]
Keywords: site-compat
I don't think this needs QA verification. If anyone thinks that's a mistake please remove the [qa-] whiteboard tag and add the verifyme keyword.
Whiteboard: [bugday-20131118] → [bugday-20131118][qa-]
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