854148 - Support for nth-child(An+B of sel) , nth-last-child(An+B of sel) pseudo classes

Status: NEW

(Core :: CSS Parsing and Computation, enhancement)

Description

[Robert Utasi [:hunboy]]

Attachment: testcase simplified (doesn't contain an+b variants)

User Agent: Mozilla/5.0 (Windows NT 5.1; rv:19.0) Gecko/20100101 Firefox/19.0
Build ID: 20130307023931

Steps to reproduce:






Expected results:

Based on discussion at Bug 854125
and following w3c selectors level 4 draft
http://dev.w3.org/csswg/selectors4/#the-nth-match-pseudo

implement nth-match, nth-last-match pseudo classes

Comment 1

[Robert Utasi [:hunboy]]

The sel4draft has been changed, nth-match, nth-last-match was removed and feature merged to nth-child with this syntax: nth-child(An+B of sel) where sel is a list of selectors

http://dev.w3.org/csswg/selectors4/#the-nth-child-pseudo

"By passing a selector argument, we can select the Nth element that matches that selector. For example, the following selector matches the first three “important” list items, denoted by the .important class:

li:nth-child(-n+3 of .important)

Note that this is different from moving the selector outside of the function, like:

li.important:nth-child(-n+3)

This selector instead just selects the first three list items if they also have the .important class."

Comment 2

[Robert Utasi [:hunboy]]

Attachment: testcase simplified (doesn't contain an+b variants)

upgrading testcase based on changes

Comment 3

[yisibl]

WebKit support: 

https://bugs.webkit.org/show_bug.cgi?id=136845
https://bugs.webkit.org/show_bug.cgi?id=137593

Comment 5

[Binyamin]

Additional testcase https://output.jsbin.com/meliga/quiet

Comment 6

[jdscharett]

Any timeframe at when this might be implemented?