Adblock Plus

Adblock Plus broken in Safari Technology Preview release 11:
https://developer.apple.com/safari/download/

The reason is that AdBlockPlus calls Event.initEvent() with a single parameter instead of 3:
./ext/content.js: beforeLoadEvent.initEvent("beforeload");
./ext/content.js: evt.initEvent(eventName);
./include.youtube.js: beforeLoadEvent.initEvent("beforeload");

As per the latest DOM specification, all 3 parameters are mandatory:
https://dom.spec.whatwg.org/#event

The standard equivalent would be to call initEvent("eventName", false, false).

You should report the issue directly on bug tracker
https://issues.adblockplus.org

I jumped the gun for him: https://issues.adblockplus.org/ticket/4361