The following test case produces different results in Edge/Firefox and Chrome/Safari:
<!DOCTYPE html>
<script>
const voidEl = document.createElement("br");
voidEl.appendChild(document.createElement("p")).textContent = "Hello Void!";
console.log(voidEl.innerHTML);
</script>Live DOM Viewer
Edge and Firefox will serialize the child nodes of the void element and log <p>Hello Void!</p>, while Chrome and Safari will log the empty string.
The algorithm used by innerHTML, Serializing HTML fragments, does contain a step where the children of void elements are skipped. However, it only applies to the child nodes of the node given as input whereas if the node given as input is itself a void element, it is not handled differently from non-void elements.
Edge and Firefox appear to be consistent with the specification as it's currently written, but given the differing implementations it may be worth considering whether the child nodes of void elements should be serialized at all.
The following test case produces different results in Edge/Firefox and Chrome/Safari:
Live DOM Viewer
Edge and Firefox will serialize the child nodes of the void element and log
<p>Hello Void!</p>, while Chrome and Safari will log the empty string.The algorithm used by innerHTML, Serializing HTML fragments, does contain a step where the children of void elements are skipped. However, it only applies to the child nodes of the node given as input whereas if the node given as input is itself a void element, it is not handled differently from non-void elements.
Edge and Firefox appear to be consistent with the specification as it's currently written, but given the differing implementations it may be worth considering whether the child nodes of void elements should be serialized at all.