<meta http-equiv="refresh" content="1;url=" /> <style> ruby::before { display: block; content: url("does-not-exist"); } </style> <ruby> <ruby> <ruby> <style> ruby { float: right; } </style> </ruby> </ruby> </ruby> <script> if (window.testRunner) testRunner.dumpAsText(); </script> This test passes if it doesn't crash.