107495 - scrollbars #2 overflow scrollbar states

Status: RESOLVED DUPLICATE of bug 12825

(Core :: XUL, defect)

Description

[rvj]

Assuming that onoverflow/onunderflow are used to catch scrollbar visibility 
changes, there needs to be a property/attribute that indicates the dynamic 
state of the scrollbars

e.g. verical, horizontal, none, both

These values can then be used to hide 

a)the appropriate static scrollbar if the overflow:scroll option is used,
b) to hide the thumb if no scrolling is possible

Currently getAttribute(style)only returns the static CSS style setting, not the 
dynamic state

Apologies if a property exists, but no response from newsgroup. If there is 
already such a property, please do tell!!

Comment 1

[rvj]

or .......

should (does) the scrollbar height and width properies always reflect ACTIVE 
scrollbar visibility?  i.e. where zero equals collapsed

in this way if an element generates an overflow event then it might be possible 
to use two scrollbar methods ( to return current height and width )to check 
scrollbar visiblity

Comment 2

[rvj]

Because xml and htm have different methods for determining content length and 
width, it appears that pageYOffset and pageXOffset provide the only general 
means of determining ACTIVE scrollbar visibility.

I have (an awful) workaround which requires scrolling the current content by 
one pixel and then checking the new offset value. If the new value is zero 
then  no scrollbar is displayed. In non-zero then the content has scrolled and 
needs to be reset back to its original value.

The problem here is that the checking is done via the onoverflow or underflow 
event. The process of restoring the original value at document extremities may 
cause unpredictable effects ( an infinite loop of scroll tests)

Is there a  simpler javascript test???

If not then a Mozilla API call ?????

Comment 3

[basic]

testcase?

Comment 4

[Daniel Wang]

*** This bug has been marked as a duplicate of 64029 ***

Comment 5

[Daniel Wang]

wrong dupe

Comment 6

[Daniel Wang]

*** This bug has been marked as a duplicate of 12825 ***