#notalljavascript (How to deal with 3rd party JS)
summary
AMP shows concrete defenses: measure visibility with IntersectionObserver instead of expensive getBoundingClientRect polling, contain third‑party code in an iframe sandbox so it can be killed and sized safely, and throttle timers by monkey‑patching setTimeout/setInterval/requestAnimationFrame (adding ~1s when offscreen) to keep the page usable. Examples include pages with 65 Flash objects, ads spawning up to 21 movies, and a JS H.264 decoder that broke performance, and the mitigations demonstrably reduce jank.
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chapters (12)
- 0:00Intro
- 0:48JavaScript is my favorite programming language.
- 1:21JavaScript is frickin awesome
- 2:27When your app starts, it makes an insecure HTTP request to my server and runs some arbitrary native code.
- 3:36Flash movies reduce their frame rate when off screen.
- 3:55I can use Flash to measure whether something is on screen.
- 7:37How does a browser parse a web page?
- 9:12Every JavaScript API will eventually be asynchronous.
- 11:42TECHNOLOGY LAB Native JavaScript H.264 decoder offers compelling demo of JS performance Mozilla has released "Broadway," a native JavaScript-based H.264 decoder that
- 12:04Chrome and Safari do not allow the tag to autoplay on mobile.
- 12:59Bandwidth still used -Battery devastated - Page janks - Only the bad players get to play video.
- 15:14Better security Control over resizing Ability to cleanly unload
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20m"Mitigating Advertising Impact on Page Performance"
13m"Don't Let Third Parties Slow You Down"
24mYou don't need AMP for that
40mHostile JavaScript: Attacking and Defending the Browser
01h 04mJavaScript's Most Wanted
41mBrowser Internals for JS Devs
29miframes: A look in to the black heart of the browsers
26mScripting in the 3rd Party True Tales of Horror and Hope