Bug 8128 – event.clientY is improperly implemented

• Status: VERIFIED
• Resolution: DUPLICATE
• Component: JavaScriptCore

[Gérard Talbot (no longer involved)]

After a few email exchanges with Beau Hartshorne, author of the article
JavaScript Events January 18, 2006
http://hartshorne.ca/2006/01/18/javascript_events/
on event properties and browser support and after checking myself in an Internet Cafe with Safari 2.02 (416.13) this page
http://www.gtalbot.org/Shieldhost/DHTMLSection/WindowEventsNS6.html
I am convinced that Safari incorrectly implements event.clientX and event.clientY

Expected results:
event.pageY = event.clientY + [amount scrolled down from top of page]
or, in Safari,
event.pageY = event.clientY + document.body.scrollTop
or
event.pageY = event.clientY + window.pageYOffset
or
event.pageY = event.clientY + window.scrollY

DOM 2 Events defines these event.clientX and clientY as related to the client area, not related to whole document width or to whole document height.

event.clientX :
"The horizontal coordinate at which the event occurred relative to the DOM implementation's client area."
http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-MouseEvent-clientX

event.clientY:
"The vertical coordinate at which the event occurred relative to the DOM implementation's client area."
http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-MouseEvent-clientY

Right now, there is also an unanimity of implementing event.clientX and event.clientY in Opera 7+, Mozilla 1.x, Seamonkey 1.x, Firefox 1.x and MSIE 6. Only Safari 2.x seems to take the x/y-coordinate of the (whole) document as the event.clientX/Y instead of the x/y-coordinate of the viewing area.

This bug is important to fix so that DHTML applications (relying on measurement, coordinating, positioning, etc.) can work reliably across browsers.

Peter-Paul Koch, at this precise url
http://www.quirksmode.org/dom/w3c_events.html#mousepos
also confirms the erroneous implementation of event.clientX/clientY in Safari: "Safari gives the mouse coordinates relative to the document which it also gives in pageX/Y."

I set version to 420+ since Beau Hartshorne data indicate that the incorrect implementation still exists in 417 / 420 .

I have searched for duplicates and did not find any. I set Component to JavaScript even though this bug is not a javascript engine bug; there does not seem to be any better component.

[Gérard Talbot (no longer involved)]

It's possible that bug 6574 involves the improper implementation of event.clientY; the DHTML code (which uses a not-so-reliable browser detect code) may fork Safari into a code branch where event.clientY is used/queried.

[David Kilzer (:ddkilzer)]

This is a known issue in Safari, confirming.

Thanks for all the great analysis, Gérard!

[David Kilzer (:ddkilzer)]

(In reply to comment #0)
> http://www.gtalbot.org/Shieldhost/DHTMLSection/WindowEventsNS6.html

This is now:

http://www.gtalbot.org/DHTMLSection/WindowEventsNS6.html

See also Bug 8707.

[Gérard Talbot (no longer involved)]

> This is now:
> http://www.gtalbot.org/DHTMLSection/WindowEventsNS6.html

Thanks for the correction. 

> See also Bug 8707.

In my opinion, bug 8707 is exactly the same as bug 8128.

[David Kilzer (:ddkilzer)]

(In reply to comment #4)
> In my opinion, bug 8707 is exactly the same as bug 8128.

Marking this bug as a duplicate of Bug 8707 per reporter's comment, and since patches are being supplied to that bug.


*** This bug has been marked as a duplicate of 8707 ***