Browser Rendering Optimization (Udacity)

Demystifying the browser's rendering pipeline will make it easy for you to build high performance web apps. By following a few simple principles, you'll be capable of drastically reducing the browser's workload and time needed to render each frame.

You'll start by getting introduce to the individual steps of the rendering pipeline, beginning with parsing HTML and ending with painting pixels on the screen. Then you'll quickly dive into tooling with ample opportunities to practice profiling and debugging apps with Chrome Developer Tools.

The final project uses the Hacker News API and gives you an opportunity to show off everything you've learned as you turn an awful experience into a high performance web app!

What You Will Learn

LESSON 1

The Critical Rendering Path

- Introduction to the course with Paul Lewis.

- Learn how the browser turns HTML into pixels on the page

- See how different CSS styles affect the rendering pipeline differently.

LESSON 2

App Lifecycles

- How to recognize the four distinct phases in an app's lifecycle: Response

- Animation

- Idle and Load (RAIL).

- How your frame budget changes depending on where the user is in RAIL.

- Practice thinking through app workloads at different stages in RAIL.

LESSON 3

Weapons of Jank Destruction

- How to make sense of the Timeline panel in Chrome DevTools.

- Practice profiling a few different apps to find the source of jank.

LESSON 4

JavaScript

- How to optimize JavaScript to hit 60fps during animations.

- How to move expensive JavaScript operations off the main thread and into Web Workers.

- How to debug a janky copy of a production quality app - the QR Snapper.

LESSON 5

Styles and Layout

- Learn how accessing the wrong CSS properties can create loads of extra work for the browser.

- Learn how to debug multiple instances of Forced Synchronous Layout.

LESSON 6

Compositing and Painting

- Practice profiling layer and paint performance with the paint profiler tool in the DevTools Timeline.

- Learn how to optimize layers to reduce the number of steps the browser needs to take to render each frame.

- Demonstrate everything you've learned about performance as you de-jankify the News Aggregator App!

Prerequisites and Requirements

You're a web developer who has written apps using HTML, CSS and JavaScript.

You have used Chrome DevTools.

(Recommended) Background knowledge about the critical rendering path from Website Performance Optimization will be helpful.