Created attachment 255336 [details] Tests support of CSSNamespaceRule Steps to reproduce the problem: Open test_case.html. What is the expected behavior? All items are "true". What went wrong? All items are "false". CSSNamespaceRule http://dev.w3.org/csswg/cssom-1/#the-cssnamespacerule-interface CSSRule.NAMESPACE_RULE http://dev.w3.org/csswg/cssom-1/#the-cssrule-interface FYI: CSS Namespaces Module Level 3 http://www.w3.org/TR/css3-namespace/ http://dev.w3.org/csswg/css-namespaces-1/ Support in other browsers: current Internet Explorer 11.0.9: Yes Firefox Nightly 33.0a1(buildID: 20140627030212): No(But CSSNameSpaceRule is supported) Opera 12.17: No(But CSSRule.NAMESPACE_RULE is supported)
Corresponding bug in blink: https://code.google.com/p/chromium/issues/detail?id=389549
Safari 15.5+ supports this feature. It passes all relevant tests.