found via bughunter and reproduced on http://www.express.co.uk/news/uk/638808/Tinder-siren-lures-man-drive-sexual-encounter-several-pints-uk with a windows 7 debug build based on todays m-c tip Assertion failure: aTargetElement->GetCurrentDoc() (we should only be able to actively animate nodes that are in a document), at c:/Users/mozilla/debug-builds/mozilla-central/layout/style/StyleAnimationValue.cpp:2596 #01: mozilla::BaseTimeDuration<mozilla::StickyTimeDurationValueCalculator>::FromTicks[xul +0x1d994d1] #02: mozilla::dom::KeyframeEffectReadOnly::BuildAnimationPropertyList[xul +0x1d9182e] #03: mozilla::dom::KeyframeEffectReadOnly::BuildAnimationPropertyList[xul +0x1d916bd] #04: mozilla::dom::KeyframeEffectReadOnly::Constructor[xul +0x1d95251] #05: mozilla::dom::Element::Animate (c:\users\mozilla\debug-builds\mozilla-central\dom\base\element.cpp:3342) #06: mozilla::dom::GetParentObject<nsIDocument,1>::Get[xul +0x2e2f72e] #07: mozilla::dom::GenericBindingMethod[xul +0x3076c0b] #08: js::CallJSNative (c:\users\mozilla\debug-builds\mozilla-central\js\src\jscntxtinlines.h:235) #09: js::Invoke (c:\users\mozilla\debug-builds\mozilla-central\js\src\vm\interpreter.cpp:475) #10: Interpret (c:\users\mozilla\debug-builds\mozilla-central\js\src\vm\interpreter.cpp:2799) #11: js::RunScript (c:\users\mozilla\debug-builds\mozilla-central\js\src\vm\interpreter.cpp:425) #12: js::Invoke (c:\users\mozilla\debug-builds\mozilla-central\js\src\vm\interpreter.cpp:493) #13: js::Invoke (c:\users\mozilla\debug-builds\mozilla-central\js\src\vm\interpreter.cpp:527) #14: js::DirectProxyHandler::call (c:\users\mozilla\debug-builds\mozilla-central\js\src\proxy\directproxyhandler.cpp:77) #15: js::CrossCompartmentWrapper::call (c:\users\mozilla\debug-builds\mozilla-central\js\src\proxy\crosscompartmentwrapper.cpp:289) #16: js::Proxy::call (c:\users\mozilla\debug-builds\mozilla-central\js\src\proxy\proxy.cpp:391) #17: js::proxy_Call (c:\users\mozilla\debug-builds\mozilla-central\js\src\proxy\proxy.cpp:683) #18: js::CallJSNative (c:\users\mozilla\debug-builds\mozilla-central\js\src\jscntxtinlines.h:235) #19: js::Invoke (c:\users\mozilla\debug-builds\mozilla-central\js\src\vm\interpreter.cpp:463) #20: Interpret (c:\users\mozilla\debug-builds\mozilla-central\js\src\vm\interpreter.cpp:2799) #21: js::RunScript (c:\users\mozilla\debug-builds\mozilla-central\js\src\vm\interpreter.cpp:425) #22: js::Invoke (c:\users\mozilla\debug-builds\mozilla-central\js\src\vm\interpreter.cpp:493) #23: js::Invoke (c:\users\mozilla\debug-builds\mozilla-central\js\src\vm\interpreter.cpp:527) #24: JS::Call (c:\users\mozilla\debug-builds\mozilla-central\js\src\jsapi.cpp:2883) #25: mozilla::dom::Function::Call[xul +0x2ee1e39] #26: mozilla::dom::Function::Call<nsCOMPtr<nsISupports> > (c:\users\mozilla\debug-builds\mozilla-central\firefox-debug\dist\include\mozilla\dom\functionbinding.h:58) #27: nsGlobalWindow::RunTimeoutHandler (c:\users\mozilla\debug-builds\mozilla-central\dom\base\nsglobalwindow.cpp:11861) #28: nsGlobalWindow::RunTimeout (c:\users\mozilla\debug-builds\mozilla-central\dom\base\nsglobalwindow.cpp:12095) #29: nsGlobalWindow::TimerCallback (c:\users\mozilla\debug-builds\mozilla-central\dom\base\nsglobalwindow.cpp:12342) #30: nsTimerImpl::Fire[xul +0x5d9c56] #31: nsTimerEvent::Run[xul +0x5c8bba] #32: nsThread::ProcessNextEvent[xul +0x5c21c7] #33: NS_ProcessNextEvent (c:\users\mozilla\debug-builds\mozilla-central\xpcom\glue\nsthreadutils.cpp:297) #34: mozilla::ipc::MessagePump::Run[xul +0xbf5ce1] #35: MessageLoop::RunInternal[xul +0xb7ca8d] #36: MessageLoop::RunHandler[xul +0xb7ca02] #37: MessageLoop::Run[xul +0xb7c60d] #38: nsBaseAppShell::Run[xul +0x40ee480] #39: nsAppShell::Run (c:\users\mozilla\debug-builds\mozilla-central\widget\windows\nsappshell.cpp:257) #40: nsAppStartup::Run[xul +0x519e61f] #41: XREMain::XRE_mainRun (c:\users\mozilla\debug-builds\mozilla-central\toolkit\xre\nsapprunner.cpp:4278) #42: XREMain::XRE_main (c:\users\mozilla\debug-builds\mozilla-central\toolkit\xre\nsapprunner.cpp:4375) #43: XRE_main (c:\users\mozilla\debug-builds\mozilla-central\toolkit\xre\nsapprunner.cpp:4477) #44: do_main (c:\users\mozilla\debug-builds\mozilla-central\browser\app\nsbrowserapp.cpp:212) #45: NS_internal_main (c:\users\mozilla\debug-builds\mozilla-central\browser\app\nsbrowserapp.cpp:352) #46: wmain (c:\users\mozilla\debug-builds\mozilla-central\toolkit\xre\nswindowswmain.cpp:131) #47: __tmainCRTStartup (f:\dd\vctools\crt\crtw32\startup\crt0.c:255) #48: BaseThreadInitThunk[kernel32 +0x4ee6c] #49: RtlInitializeExceptionChain[ntdll +0x63ab3] #50: RtlInitializeExceptionChain[ntdll +0x63a86] mozilla@win-7-battlestar ~/debug-builds/mozilla-central/firefox-debug/dist/bin

This crash is the same as bug 1239889.