V8 implements a large subset of the JavaScript language’s built-in objects and functions in JavaScript itself. For example, you can see our promises implementation is written in JavaScript. Such built-ins are called self-hosted. These implementations are included in our startup snapshot so that new contexts can be quickly created without needing to setup and initialize the self-hosted built-ins at runtime.

Roughly every six weeks, we create a new branch of V8 as part of our release process. Each version is branched from V8’s Git master immediately before Chrome branches for a Chrome Beta milestone. Today we’re pleased to announce our newest branch, V8 version 4.9, which will be in beta until it is released in coordination with Chrome 49 Stable. V8 4.9 is filled with all sorts of developer-facing goodies, so we’d like to give you a preview of some of the highlights in anticipation of the release in several weeks.

Math.random() returns a Number value with positive sign, greater than or equal to 0 but less than 1, chosen randomly or pseudo-randomly with approximately uniform distribution over that range, using an implementation-dependent algorithm or strategy. This function takes no arguments.

Roughly every six weeks, we create a new branch of V8 as part of our release process. Each version is branched from V8’s Git master immediately before Chrome branches for a Chrome Beta milestone. Today we’re pleased to announce our newest branch, V8 version 4.8, which will be in beta until it is released in coordination with Chrome 48 Stable. V8 4.8 contains a handful of developer-facing features, so we’d like to give you a preview of some of the highlights in anticipation of the release in several weeks.

Jank, or in other words visible stutters, can be noticed when Chrome fails to render a frame within 16.66 ms (disrupting 60 frames per second motion). As of today most of the V8 garbage collection work is performed on the main rendering thread, c.f. Figure 1, often resulting in jank when too many objects need to be maintained. Eliminating jank has always been a high priority for the V8 team (1, 2, 3). This article discusses a few optimizations that were implemented between Chrome 41 and Chrome 46 which significantly reduce garbage collection pauses resulting in better user experience.

Roughly every six weeks, we create a new branch of V8 as part of our release process. Each version is branched from V8’s Git master immediately before Chrome branches for a Chrome Beta milestone. Today we’re pleased to announce our newest branch, V8 version 4.7, which will be in beta until it is released in coordination with Chrome 47 Stable. V8 v4.7 is filled with all sorts of developer-facing goodies, so we’d like to give you a preview of some of the highlights in anticipation of the release in several weeks.

The JavaScript specification includes a lot of built-in functionality, from math functions to a full-featured regular expression engine. Every newly-created V8 context has these functions available from the start. For this to work, the global object (for example, the window object in a browser) and all the built-in functionality must be set up and initialized into V8’s heap at the time the context is created. It takes quite some time to do this from scratch.

Roughly every six weeks, we create a new branch of V8 as part of our release process. Each version is branched from V8’s Git master immediately before Chrome branches for a Chrome Beta milestone. Today we’re pleased to announce our newest branch, V8 version 4.6, which will be in beta until it is released in coordination with Chrome 46 Stable. V8 4.6 is filled with all sorts of developer-facing goodies, so we’d like to give you a preview of some of the highlights in anticipation of the release in several weeks.

JavaScript performance continues to be one of the key aspects of Chrome’s values, especially when it comes to enabling a smooth experience. Starting in Chrome 41, V8 takes advantage of a new technique to increase the responsiveness of web applications by hiding expensive memory management operations inside of small, otherwise unused chunks of idle time. As a result, web developers should expect smoother scrolling and buttery animations with much reduced jank due to garbage collection.

V8 uses just-in-time compilation (JIT) to execute JavaScript code. This means that immediately prior to running a script, it has to be parsed and compiled — which can cause considerable overhead. As we announced recently, code caching is a technique that lessens this overhead. When a script is compiled for the first time, cache data is produced and stored. The next time V8 needs to compile the same script, even in a different V8 instance, it can use the cache data to recreate the compilation result instead of compiling from scratch. As a result the script is executed much sooner.