The Performance Timeline API defines extensions to the Performance interface to support client-side latency measurements within applications. The extensions provide interfaces to retrieve performance entry metrics based on specific filter criteria. The standard also includes interfaces that allow an application to define performance observer callbacks that are notified when specific performance events are added to the browser's performance timeline.
The Performance Timeline standard defines extensions to the Performance interface to support client-side latency measurements within applications. The standard also includes interfaces that allow an application to be notified when specific performance events occur. Together, these interfaces can be used to help identify an application's performance bottlenecks.
Pointer events extend DOM input events to support various pointing input devices such as pen/stylus and touch screens as well as mouse. The pointer is a hardware-agnostic device that can target a specific set of screen coordinates. Having a single event model for pointers can simplify creating Web sites, applications and provide a good user experience regardless of the user's hardware.
Adding gestures to an application can significantly improve the user experience. There are many types of gestures, from the simple single-touch swipe gesture to the more complex multi-touch twist gesture, where the touch points (aka pointers) move in different directions.
This document demonstrates how to use pointer events and <canvas> to build a multi-touch enabled drawing application. This example is identical to the application described in the Touch events Overview except this example uses the pointer events input event model (instead of touch events. Another difference is that because pointer events are pointer device agnostic, the application accepts both touch input, pen and mouse input, the latter two for free.
The Resource Timing interfaces enable retrieving and analyzing detailed network timing data regarding the loading of an application's resource(s). An application can use the timing metrics to determine, for example, the length of time it takes to load a specific resource, such as an XMLHttpRequest, <SVG>, image, or script.
The Resource Timing interfaces enable retrieving and analyzing detailed network timing data regarding the loading of an application's resource(s). An application can use the timing metrics to determine, for example, the length of time it takes to fetch a specific resource such as an XMLHttpRequest, <SVG>, image, script, etc.).
The touch event interfaces support application-specific single and multi-touch interactions. However, the interfaces can be a bit tricky for programmers to use because touch events are very different from other DOM input events, such as mouse events. The application described in this guide shows how to use touch events for simple single and multi-touch interactions, the basics needed to build application-specific gestures.
The touch interfaces enable applications to create enhanced user experiences on touch enabled devices. However, the reality is the vast majority of today's web content is designed only to work with mouse input. Consequently, even if a browser supports touch, the browser must still emulate mouse events so content that assumes mouse-only input will work as is without direct modification.
Today, most Web content is designed for keyboard and mouse input. However, devices with touch screens (especially portable devices) are mainstream and Web applications can either directly process touch-based input by using Touch Events or the application can use interpreted mouse events for the application input. A disadvantage to using mouse events is that they do not support concurrent user input, whereas touch events support multiple simultaneous inputs (possibly at different locations on the touch surface), thus enhancing user experiences.
WebSockets is a technology, based on the ws protocol, that makes it possible to establish a continuous full-duplex connection stream between a client and a server. A typical websocket client would be a user's browser, but the protocol is platform independent.
Dynamic Adaptive Streaming over HTTP (DASH) is an adaptive streaming protocol. This means that it allows for a video stream to switch between bit rates on the basis of network performance, in order to keep a video playing.
JavaScript supports a compact set of statements, specifically control flow statements, that you can use to incorporate a great deal of interactivity in your application. This chapter provides an overview of these statements.
JavaScript is an object-based language based on prototypes, rather than being class-based. Because of this different basis, it can be less apparent how JavaScript allows you to create hierarchies of objects and to have inheritance of properties and their values. This chapter attempts to clarify the situation.
This chapter introduces collections of data which are ordered by an index value. This includes arrays and array-like constructs such as Array objects and TypedArray objects.
Processing each of the items in a collection is a very common operation. JavaScript provides a number of ways of iterating over a collection, from simple for loops to map() and filter(). Iterators and Generators bring the concept of iteration directly into the core language and provide a mechanism for customizing the behavior of for...of loops.
Loops offer a quick and easy way to do something repeatedly. This chapter of the JavaScript Guide introduces the different iteration statements available to JavaScript.
Starting with ECMAScript 6, JavaScript gains support for the Proxy and Reflect objects allowing you to intercept and define custom behavior for fundamental language operations (e.g. property lookup, assignment, enumeration, function invocation, etc). With the help of these two objects you are able to program at the meta level of JavaScript.
By modifying the coordinate space, CSS transforms change the shape and position of the affected content without disrupting the normal document flow. This guide provides an introduction to using transforms.