<html><head> <title>Crash [@ nsGenericElement::SetAttr] with classList.toggle</title> <script> var classList; var interval; function run() { classList = window.frames[0].document.documentElement.classList; window.frames[0].location.reload(); interval = setInterval(function(aClassList) {aClassList.toggle('a'); forcegc();}, 10, classList); // Let the interval run for awhile and close the window after 2 seconds. setTimeout(function() { clearInterval(interval); window.opener.done(); window.close(); }, 2000); } function forcegc(){ SpecialPowers.forceGC(); SpecialPowers.gc(); } </script> </head> <body onload="run()"> <iframe></iframe> </body> </html>