Performance features

Animation Timing API

The Animation Timing API provides a smoother and more efficient way to create animated webpages by calling the animation frame when the system is ready to paint the frame. This helps you avoid overdrawn animations, wasted CPU cycles, and unnecessary power usage.

Beacon API

The Beacon API provides a way to efficiently send beacons of critical information to a server.

Efficient Script Yielding

Use setImmediate to solve the problems of using setTimeout by addressing the core performance problem without negatively impacting power consumption. Flush the browser event queue and receive an immediate callback without the minimum delays enforced by setTimeout.

Fetch API

The Fetch API is the modern-day replacement for XMLHttpRequest that allows for low-level handling of responses and requests, as well as the ability to stream data.

The Navigation Timing API makes it easy to measure the real-world speed and performance of websites and locate problem areas that need tuning.

Page Visibility API

The Page Visibility API provides a means for developers to determine the current visibility of a document (or whether the page is in focus) and be notified when the visibility changes.

Prerender and prefetch support

Prerender and prefetch support enables content to download before it is needed so that resources are instantly available when the user wants them.

Resource Timing API

The Resource Timing API allows web applications to access network timing information regarding how long it takes for resources to load in a document.

Streams API

The Streams API enables streaming of chunks of data from streams.

User Timing API

The User Timing API enables developers to accurately measure the length of AJAX requests, report on performance, and create benchmarks for JavaScript code using high precision timestamps.


Use XMLHttpRequest to transfer data to and from a client and server.