<!DOCTYPE html>
<script>
try { document.createElementNS("a", "a:0") }
catch(e) { document.documentElement.textContent = e.name }
</script>Outputs InvalidCharacterError in Chrome, Firefox, and Edge. Per spec, it should throw NamespaceError, because "a:0" matches the Name production. I think browsers should probably change here instead of the spec, because browsers' behavior doesn't make sense to me, but I'm filing a spec bug anyway because we seem to have interop against the spec.
Outputs InvalidCharacterError in Chrome, Firefox, and Edge. Per spec, it should throw NamespaceError, because "a:0" matches the Name production. I think browsers should probably change here instead of the spec, because browsers' behavior doesn't make sense to me, but I'm filing a spec bug anyway because we seem to have interop against the spec.