Interesting... there have been lots of times I've wanted this kind of functionality in jQuery selectors or XPath...
But I just realized I've never once felt like I needed it in CSS. Can anyone give me a real-world example where this would actually be useful for styling? I almost worry this might make CSS more difficult to understand, rather than easier to write.
It would be helpful in cases of dynamically inserting markup into the page. If the CSS was coded to account for the possibilities then you only have to insert your new HTML into the page without having to add a class to its parent.
Say, an unordered list and the list items it contains can be styled based on the content that the list items may happen to contain; again without having to add classes to the parents.
Or maybe a form, you can add an error class to one of the inputs and then style the entire form based on the fact that one of the inputs has the error class.
Another use if you have one person entering text, such as with a CMS, then you can have another person code the CSS to handle differently possibilities of what different parents might contain. That way the person entering the text through a WYSIWYG editor wouldn't have to worry over adding classes to the parents while editing. It'll just happen.
It's not one of those features that will change CSS as we know it but it would be a useful feature. Over the years there were times I really wished I had this feature, mostly because it involved server-side generated HTML that would be a pain to get altered for one reason or another.
:has has been a part of jquery for forever. XPath has axis which allows similar expressive powers.
As noted elsewhere in the comments, this has been long (a decade plus) planned for "some future CSS" by editors and contributors. It didn't make the cut for selectors level 3 for reasons discussed in other comments here. It is currently part of 4 in potentially modified (and less powerful) form.
Personally, I find myself wanting it all the time. I frequently find myself littering HTML with (otherwise nonsensical) classes to achieve the sorts of things that this makes easy.
Comments
Interesting... there have been lots of times I've wanted this kind of functionality in jQuery selectors or XPath...
But I just realized I've never once felt like I needed it in CSS. Can anyone give me a real-world example where this would actually be useful for styling? I almost worry this might make CSS more difficult to understand, rather than easier to write.
It would be helpful in cases of dynamically inserting markup into the page. If the CSS was coded to account for the possibilities then you only have to insert your new HTML into the page without having to add a class to its parent.
Say, an unordered list and the list items it contains can be styled based on the content that the list items may happen to contain; again without having to add classes to the parents.
Or maybe a form, you can add an error class to one of the inputs and then style the entire form based on the fact that one of the inputs has the error class.
Another use if you have one person entering text, such as with a CMS, then you can have another person code the CSS to handle differently possibilities of what different parents might contain. That way the person entering the text through a WYSIWYG editor wouldn't have to worry over adding classes to the parents while editing. It'll just happen.
It's not one of those features that will change CSS as we know it but it would be a useful feature. Over the years there were times I really wished I had this feature, mostly because it involved server-side generated HTML that would be a pain to get altered for one reason or another.
:has has been a part of jquery for forever. XPath has axis which allows similar expressive powers.
As noted elsewhere in the comments, this has been long (a decade plus) planned for "some future CSS" by editors and contributors. It didn't make the cut for selectors level 3 for reasons discussed in other comments here. It is currently part of 4 in potentially modified (and less powerful) form.
Personally, I find myself wanting it all the time. I frequently find myself littering HTML with (otherwise nonsensical) classes to achieve the sorts of things that this makes easy.