Modern websites are often composed out of megabytes of JavaScript – not all of which we wrote ourselves: Ads, social plugins, tweets, instagrams, video players and other things get assembled together and more often than not don’t play all too well with each other. When we started the AMP project we quickly realized we’d have to support this type of third party JS. In this talk we’ll do a deep dive into how we manage to maintain page performance and decent user experience nonetheless. Bring your wetsuit, because we’ll dive deep into some of the more rarely explored corners of the JavaScript language.