- October 9, 2026In an HTML document, script-supporting elements are those elements that don't directly contribute to the appearance or layout of the…
- October 9, 2026Screen readers are software applications that attempt to convey what is seen on a screen display in a non-visual way,…
- October 9, 2026The scope is the current context of execution in which values and expressions are "visible" or can be referenced.
- October 9, 2026SCM (Source Control Management) is a system for managing source code.
- October 9, 2026An HTTP method is safe if it doesn't alter the state of the server.
- October 9, 2026In cryptography, salt is random data added to a password before it is hashed.
- October 9, 2026A robots meta tag gives supported crawlers page-level indexing or presentation instructions, such as noindex.
- October 9, 2026REST (Representational State Transfer) refers to a group of software architecture design constraints that bring about efficient, reliable and scalable…
- October 9, 2026Responsive design adapts a website's layout and presentation to available viewport space and user needs.
- October 9, 2026A response header is an HTTP header that can be used in an HTTP response and that doesn't relate to…
- October 9, 2026A request header is an HTTP header that can be used in an HTTP request to provide information about the…
- October 9, 2026The following are treated as replaced elements only in specific cases:
- October 9, 2026In web security, a replay attack happens when an attacker intercepts a previously-sent message and resends it later to get…
- October 9, 2026A representation header (or 'representation metadata') is an HTTP header that describes how to interpret the data contained in the…
- October 9, 2026Repaint happens when a browser redraws a web page to show the visual updates resulting from a UI change, such…
- October 9, 2026Render-blocking refers to any part of the process of loading a website that blocks the rendering of the user interface.
- October 9, 2026A relying party (RP) is an entity that needs to control access to a resource and, to do so, needs…
- October 9, 2026Regular expressions (or regex) are rules that govern which sequences of characters come up in a search.
- October 9, 2026A registrable domain is a domain that can be (or has already been) registered by an individual or an organization…
- October 9, 2026Reflow happens when a browser recalculates the position and geometry of certain parts of a webpage, such as after an…
- October 9, 2026Real User Monitoring (RUM) measures the performance of a page from real users' machines.
- October 9, 2026The act of a function calling itself, recursion is used to solve problems that contain smaller sub-problems.
- October 9, 2026Reading order refers to the order in which content is accessed, for example when read out by a screen reader,…
- October 9, 2026A raster image is an image file defined as a grid of pixels.
- October 9, 2026In computing, especially in networking, rate limiting means controlling how many operations can be performed in a given amount of…
- October 9, 2026RAIL, an acronym for Response, Animation, Idle, and Load, is a performance model originated by the Google Chrome team in…
- October 9, 2026QUIC is a multiplexed transport protocol implemented on UDP.
- October 9, 2026Quality values, or q-values and q-factors, are used to describe the order of priority of values in a comma-separated list.
- October 9, 2026A quaternion is the quotient of two 3D vectors and is used in 3D graphics and in accelerometer-based sensors to…
- October 9, 2026Progressive enhancement starts with usable core content and interaction, then adds capabilities when the user's browser supports them.
- October 9, 2026Prefetching refers to the practice of speculatively fetching documents or subresources in the background for pages that the user is…
- October 9, 2026For a computer connected to a network with an IP address, a port is a communication endpoint.
- October 9, 2026Polymorphism is the presentation of one interface for multiple data types.
- October 9, 2026POP3 (Post Office Protocol) is a very common protocol for getting emails from a mail server over a TCP connection.
- October 9, 2026A polyfill is a piece of code (usually JavaScript on the Web) used to provide modern functionality on older browsers…
- October 9, 2026Plaintext refers to information that is being used as an input to an encryption algorithm, or to ciphertext that has…
- October 9, 2026Placeholder names are commonly used in cryptography to indicate the participants in a conversation, without resorting to terminology such as…
- October 9, 2026A pixel is the smallest building block of a graphical display like a computer screen.
- October 9, 2026CSS physical properties define positions based on physical directions or element sides.
- October 9, 2026Percent-encoding is a mechanism to encode 8-bit characters that have specific meaning in the context of URLs.
- October 9, 2026A payload header is an HTTP header that describes the payload information related to safe transport and reconstruction of the…
- October 9, 2026In HTTP messages, the payload body or payload was the resource representation transferred in a message body, stripped of any…
- October 9, 2026Parsing means analyzing and converting a program into an internal format that a runtime environment can actually run, for example…
- October 9, 2026Parameters are named variables declared as part of a function.
- October 9, 2026Page load time is the time it takes for a page to load, measured from navigation start to the start…
- October 9, 2026Page Prediction is a browser feature or script which, when enabled, tells the browser to download resources the user is…
- October 9, 2026A Proxy Auto-Configuration file (PAC file) is a file which contains a function, FindProxyForURL(), which is used by the browser…
- October 9, 2026A packet, or network packet, is a formatted chunk of data sent over a network.
- October 9, 2026Over The Air (OTA) refers to automatic updating of software on connected devices from a central server.
- October 9, 2026Out-of-order patching refers to delivering HTML content in an order different from the sequential, top-to-bottom flow of a single document.
- October 9, 2026Web content's origin is defined by the scheme (protocol), hostname (domain), and port of the URL used to access it.
- October 9, 2026Open Graph metadata describes a page for services that generate link previews.
- October 9, 2026OOP (Object-Oriented Programming) is an approach in programming in which data is encapsulated within objects and the object itself is…
- October 9, 2026An object reference is a link to an object.
- October 9, 2026In JavaScript, objects can be seen as a collection of properties.
- October 9, 2026Normative is a word commonly used in software specifications to denote sections that are standardized and must be followed as…
- October 9, 2026In computer science, a null value represents a reference that points, generally intentionally, to a nonexistent or invalid object or…
- October 9, 2026Software specifications often contain information marked as non-normative or informative, which is provided to help readers understand the specification better,…
- October 9, 2026In cryptography and computer security, a nonce is an arbitrary number that is used only once in a cryptographic communication.
- October 9, 2026Node.js is a cross-platform JavaScript runtime environment that allows developers to build server-side and network applications with JavaScript.
- October 9, 2026Network throttling is an intentional slowing down of internet speed.
- October 9, 2026A native application has been compiled to run on the hardware/software environment that comprises the targeted architecture.
- October 9, 2026Namespace is a context for identifiers, a logical grouping of names used in a program.
- October 9, 2026NaN (Not a Number) is a numeric data type that means an undefined value or value that cannot be represented,…
- October 9, 2026A mutable value is one that can be changed without creating an entirely new value, in comparison with immutable values.
- October 9, 2026MVC (Model-View-Controller) is a pattern in software design commonly used to implement user interfaces, data, and controlling logic.
- October 9, 2026Multi-factor authentication (MFA) is an authentication method in which the user has to present more than one type of evidence…
- October 9, 2026A mixin is a class (interface, in WebAPI spec terms) in which some or all of its methods and/or properties…
- October 9, 2026Mobile first, a form of progressive enhancement, is a web-development and web-design approach that focuses on prioritizing design and development…
- October 9, 2026A modem ("modulator-demodulator") is a device that converts digital information to analog signals and vice versa, for sending data through…
- October 9, 2026A manipulator in the middle attack (MitM) intercepts a communication between two systems.
- October 9, 2026Minification is the process of removing unnecessary or redundant data without affecting how a resource is processed by the browser.
- October 9, 2026Middleware is a (loosely defined) term for any software or service that enables the parts of a system to communicate…
- October 9, 2026A MIME type (now properly called "media type", but also sometimes "content type") is a string sent along with a…
- October 9, 2026A method is a function which is a property of an object.
- October 9, 2026Memoization is an optimization technique that stores the result of a function call and returns the stored result when the…
- October 9, 2026The term media (more accurately, multimedia) refers to audio, video, or combined audio-visual material such as music, recorded speech, movies,…
- October 9, 2026In the context of CSS (Cascading Style Sheets), the term media refers to the destination to which the document is…
- October 9, 2026A media query is a logical expression that is a method for CSS, JavaScript, HTML, and other web languages, to…
- October 9, 2026A markup language is one that is designed for defining and presenting text.
- October 9, 2026The main thread is where a browser processes user events and paints.
- October 9, 2026The main axis in flexbox is defined by the direction set by the flex-direction property.
- October 9, 2026Lossy compression, or irreversible compression, is a data-compression method that uses inexact approximations and partial-data discarding to represent content.
- October 9, 2026LTR (Left To Right) is a locale property indicating that text is written from left to right.
- October 9, 2026Lossless compression is a class of data compression algorithms that allows the original data to be perfectly reconstructed from the…
- October 9, 2026A long task is a task that takes more than 50ms to complete.
- October 9, 2026A loop is a sequence of instructions that is repeated until a certain condition is met.
- October 9, 2026CSS logical properties provide a way to lay out content based on the document's writing mode and direction rather than…
- October 9, 2026Localization (l10n) is the process of adapting a software user interface to a specific culture.
- October 9, 2026Locale is a set of language- or country-based preferences for a user interface.
- October 9, 2026Literals represent values in JavaScript.
- October 9, 2026LGPL (GNU Lesser General Public License) is a free software license published by the Free Software Foundation.
- October 9, 2026In typography, leading is an amount of space included above and below text to provide spacing between lines.
- October 9, 2026A layout mode, sometimes called layout, is a CSS algorithm that determines the position and size of element boxes based…
- October 9, 2026The layout viewport is the viewport into which the browser draws a web page.
- October 9, 2026Lazy loading is a strategy that delays the loading of some assets (e.g., images) until they are needed by the…
- October 9, 2026Latency is the network time it takes for a requested resource to reach its destination.
- October 9, 2026The Largest Contentful Paint (LCP) performance metric provides the render time of the largest image or text block visible within…
- October 9, 2026A key is a piece of information used by a cipher for encryption and/or decryption.
- October 9, 2026A keyword is a word or phrase that describes content.
