z-ordering

There are some serious discrepancies between the z-ordering described
in section 9.9 of CSS2 [1] and what is implemented in browsers.  The
main problem is that the default value of 'z-index' has not been
implemented as 'auto', but rather, some other mysterious behavior.  The
two things that I think should occur with 'auto' but do not in current
browsers [2] are:

1) By default, positioned elements do not create a new stacking
context.  This means other elements can come between them and their
children.

2) By default, positioned elements are not "above" non-positioned
elements, but are drawn in document order so that they are above
elements before them in the document (just as other elements are).

Are my descriptions correct?  Should future implementations use the
spec's rules, or should the spec be considered changed because of the
way z-ordering has already been implemented?  If so, how?

David

[1] http://www.w3.org/TR/REC-CSS2/visuren.html#q30
[2] see my test at http://www.fas.harvard.edu/~dbaron/css/test/sec0909

L. David Baron     Rising Sophomore, Harvard     dbaron@fas.harvard.edu
Links, SatPix, CSS, etc.        < http://www.fas.harvard.edu/~dbaron/ >

Received on Monday, 28 June 1999 10:27:38 UTC