The @media CSS rule conditionally applies styles based on the output device type, its capabilities, and the user's preferences. Media queries are composed of an optional media type such as screen or print, and one or more mandatory media features, such as prefers-reduced-animations.

The JSON API provides static methods for parsing values from and converting values to JavaScript Object Notation (JSON), a serialization format for objects, arrays, numbers, strings, Boolean values, and null.

Functions are series of statements that can be called and return a value. The function keyword (as in function () { }) and arrow (=>) expression create functions. The JavaScript functions protocol includes default and rest parameters and binding to this.

The white-space CSS property sets how white space is collapsed and how lines wrap. It is a shorthand for white-space-collapse and text-wrap-mode.

The opacity CSS property sets the transparency of an element.

The string type (and String object) represents a sequence of characters.

The currentColor CSS value allows you to reuse an element's computed text color for other properties.

Some CSS color values can be referenced by name, such as red or limegreen. They stand in for specific RGB color values.

The system color CSS keywords, such as ButtonBorder or LinkText, allow you to match default colors from the user agent.

The font-variant CSS property is a shorthand for font-variant-alternates, font-variant-caps, font-variant-east-asian, font-variant-emoji, font-variant-ligatures, font-variant-numeric, and font-variant-position.

The <label> HTML element represents a caption for a form field.

The WebGLRenderingContext API is the "webgl" rendering context for the <canvas> element. It represents a space for drawing two- and three-dimensional graphics and animations.

The CanvasRenderingContext2D API is the "2d" rendering context for the <canvas> element. It represents a flat, two-dimensional space for drawing graphics and animations.

The Date object represents a single moment in time.

The number type (and Number object) represents floating-point numbers, such as 42 or -4.201, while the Math API contains mathematical functions and constants. JavaScript can also represent boundless negative and positive values as Infinity or not-a-number as NaN (as in 0 * Infinity).

The navigator.geolocation API requests the user's latitude, longitude, heading, and speed.

The z-index CSS property orders overlapping elements, with higher values appearing in front of or on top of lower values.

The <form> element contains interactive controls for submitting information.

The RegExp object represents a regular expression, a notation for matching text patterns.

The <link> element creates a relationship between the current document and an external resource, such as a stylesheet or favicon.

A WeakMap object holds key-value pairs that do not create strong references to its keys, such that value data can be associated with a key without preventing garbage collection of the key.

The <select> element provides a menu of options for a user to pick from, typically rendered as a dropdown list.

The @import CSS at-rule loads styles from another stylesheet.

The <style> element embeds an inline CSS stylesheet in a document.

The <fieldset> and <legend> elements group several form control elements within a web form.

The <ins> element represents a range of text that has been inserted into a document, styling text as underlined by default.

The <progress> element displays an indicator showing the completion progress of a task, typically displayed as a progress bar.

The <button> HTML element represents a button that triggers some action, such as submitting a form or opening a dialog, styled as a labeled rectangular box by default.

The <object> element represents an external resource such as a PDF or SVG document. It was historically used for plugins such as Shockwave Flash.

The <textarea> element represents an editing control that allows users to enter multi-line, free-form, plain text.