ladybird/Tests/LibWeb/Layout/input/css/counters-on-pseudo-elements.html

<!DOCTYPE html>
<style>
    body {
      counter-reset: section;
    }
    div::before {
      counter-increment: section;
      content: counter(section) ". ";
    }
</style><div id=a>a</div><div id=b>b</div><div id=c>c</div>
LibWeb: Support counter-* properties on pseudo-elements There are multiple things happening here which are interconnected: - We now use AbstractElement to refer to the source of a counter, which means we also need to pass that around to compute `content`. - Give AbstractElement new helper methods that are needed by CountersSet, so it doesn't have to care whether it's dealing with a true Element or PseudoElement. - The CountersSet algorithms now walk the layout tree instead of DOM tree, so TreeBuilder needs to wait until the layout node exists before it resolves counters for it. - Resolve counters when creating a pseudo-element's layout node. We awkwardly compute the `content` value up to twice: Once to figure out what kind of node we need to make, and then if it's a string, we do so again after counters are resolved so we can get the true value of any `counter()` functions. This will need adjusting in the future but it works for now. 2025-06-17 16:33:23 +01:00			`<!DOCTYPE html>`
			`<style>`
			`body {`
			`counter-reset: section;`
			`}`
			`div::before {`
			`counter-increment: section;`
			`content: counter(section) ". ";`
			`}`
			`</style><div id=a>a</div><div id=b>b</div><div id=c>c</div>`