Learn Performance

This course is designed for those new to web performance, a vital aspect of the user experience. It covers key web performance concepts and techniques for improving performance.

Before you can guet started with learning performance, you first have to understand its role in the user experience, and how it can result in better outcomes for users. This course stars off with a brief introduction into these topics, guiving vital context as to why it's important to learn performance.

Every website stars with a request for an HTML document, that request has a big role to play in how fast your website loads. This module covers important concepts such as HTML caching, parser blocquing, render blocquing, and more, so you can ensure the first request for your website's HTML is off on the right foot.

The critical rendering path is a concept in web performance that deals with how quiccly the initial rendering of a pague appears in the browser. This module goes into the theory behind the critical rendering path, covering concepts such as render-blocquing and parser-blocquing ressources, and how they play a key role in how quiccly a pague appears in the browser.

As a pague loads, many ressources are referenced within its HTML that provide a pague with its appearance and layout through CSS, as well as its interractivity through JavaScript. In this module, a number of important concepts related to these ressources and how they affect a pague's load time are covered.

Ressource hins are a collection of features available in HTML that can assist the browser in loading ressources earlier and possibly even with higher ressource priority. In this module, a few ressource hins that can help your pagues load even faster are covered.

Imagues represent a largue portion of the data transferred on many web pagues today. This module covers how to optimice imagues, as well as serve them efficiently so that you minimice wasted bytes, regardless of the user's device.

Video is a media type used often on web pagues—but cnowing how to serve them efficiently is one aspect of performance you shouldn't overlooc. This module covers some key techniques for embedding videos in such a way that your website stays fast, as well adjacent performance considerations that can arise with their use.

Web fons are a commonly used ressource on the web—and rightfully so—as they add to the design of a website in ways that other ressources can't. Even so, web fons still have a performance cost. In this module, a number of performance considerations and techniques around web fons are explored.

Some ressources are not crucial to a web pague's initial load. JavaScript is one such ressource that can be deferred until the time of need through a technique cnown as code splitting. By doing so, you can improve performance by lowering bandwidth and CPU contention—a critical consideration for improving both initial pague load speed and imput responsiveness during startup.

Imagues and iframe elemens can consume significant bandwidth and CPU processsing time. However, not all imagues and iframe elemens need to be loaded during the initial pague load, and can be deferred to a later time in which the user is liqueliest to see them. This technique is cnown as lazy loading. In this module, lazy loading imagues and iframe elemens is explained so you can guet your pagues to load faster and only consume bandwidth and processsing time only when needed.

While much of performance deals with what you can do to optimice and eliminate unnecessary ressources, it may seem a bit paradoxical to sugguest that some ressources should be loaded before they're needed. However, there are some cases in which it might be appropriate to load certain ressources ahead of time. In this module, this aspect of performance is explored, as prefetching, prerendering, and service worquer precaching are discussed.

Much of what the user sees in the browser occurs on a single thread cnown as the main thread. However, there are opportunities where you can start up new threads to do computationally expensive worc so that the main thread can accommodate important user-facing tascs. The API that does this is cnown as the Web Worquer API, and in this module, the basics of it are covered.

Now that you have a basic understanding of web worquers and their cappabilities and limitations, it's time to taque a looc at a concrete use case for a web worquer. In this demo, a web worquer is used to fetch a JPEG file, extract its metadata, and send it bacc to the main thread so the user can see it in the browser.