CRUD is an acronym for Create, Read/Retrieve, Update, Delete, which denote the four basic data management operations to be performed by any software application.

Cascading Style Sheets

CSS is used for defining the presentation style of web pages by telling the browser how to render their HTML (or XML) contents: using which layout of content elements, which fonts and text styles, which colors, which backgrounds, and which animations. Normally, these settings are made in a separate CSS file that is associated with an HTML file via a special link element in the HTML's head element.


Document Object Model

The DOM is an abstract API for retrieving and modifying nodes and elements of HTML or XML documents. All web programming languages have DOM bindings that realize the DOM.

Domain Name System

The DNS translates user-friendly domain names to IP addresses that allow to locate a host computer on the Internet.



A standard for JavaScript defined by the industry organization "Ecma International".

Extensible Markup Language

XML allows to mark up the structure of all kinds of documents, data files and messages in a machine-readable way. XML may also be human-readable, if the tag names used are self-explaining. XML is based on Unicode. SVG and MathML are based on XML, and there is an XML-based version of HTML.

XML provides a syntax for expressing structured information in the form of an XML document with elements and their attributes. The specific elements and attributes used in an XML document can come from any vocabulary, such as public standards or user-defined XML formats.


Hypertext Markup Language

HTML allows marking up (or describing) the structure of a human-readable web document or web user interface. The XML-based version of HTML, which is called "XHTML5", provides a simpler and cleaner syntax compared to traditional HTML.

Hypertext Transfer Protocol

HTTP is a stateless request/response protocol based on the Internet technologies TCP/IP and DNS, using human-readable text messages for the communication between web clients and web servers. The main purpose of HTTP has been to allow fetching web documents identified by URLs from a web browser, and invoking the operations of a back-end web application program from an HTML form executed by a web browser. More recently, HTTP is increasingly used for providing web APIs and web services.



IANA stands for Internet Assigned Numbers Authority, which is a subsidiary of ICANN responsible for names and numbers used by Internet protocols.


ICANN stands for Internet Corporation of Assigned Names and Numbers, which is an international nonprofit organization that maintains the domain name system.


A JavaScript API for indexed data storage managed by browsers. Indexing allows high-performance searching. Like many SQL DBMS, IndexedDB supports database transactions.


A set of best practices that help to adapt products to any target language and culture. It deals with multiple character sets, units of measure, keyboard layouts, time and date formats, and text directions.



JSON stands for JavaScript Object Notation, which is a data-interchange format following the JavaScript syntax for object literals. Many programming languages support JSON as a light-weight alternative to XML.



An open standard for representing mathematical expressions, either in data interchange or for rendering them within webpages.


A MIME type (also called "media type" or "content type") is a keyword string sent along with a file for indicating its content type. For example, a sound file might be labeled audio/ogg, or an image file image/png.


MVC is a general architecture metaphor emphasizing the principle of separation of concerns, mainly between the model and the view, and considering the model as the most fundamental part of an app. In MVC frameworks, "M", "V" and "C" are defined in different ways. Often the term “model” refers to the app’s data sources, while the “view” denotes the app’s code for the user interface, which is based on CSS-styled HTML forms and DOM events, and the “controller” typically denotes the (glue) code that is in charge of mediating between the view and the model.


Object Constraint Language

The OCL is a formal logic language for expressing integrity constraints, mainly in UML class models. It also allows defining derivation expressions for defining derived properties, and defining preconditions and postconditions for operations, in a class model..

Object-Oriented Programming

OOP is a programming paradigm based on the concepts of objects and classes instantiated by objects. Classes are like blueprints for objects: they define their properties and the methods/functions that can be applied to them. A higher-level characteristic of OOP is inheritance in class hierarchies: a subclass inherits the features (properties, methods and constraints) of its superclass.

Web Ontology Language

OWL is formal logic language for knowledge representation on the Web. It allows defining vocabularies (mainly classes with properties) and supports expressing many types of integrity constraints on them. OWL is the basis for performing automated inferences, such as checking the consistency of an OWL vocabulary. Vocabularies, or data models, defined in the form of UML class models can be converted to OWL vocabularies and then checked for consistency.


Portable Network Graphics

PNG is an open (non-proprietary) graphics file format that supports lossless data compression.


A polyfill is a piece of JavaScript code for emulating a standard JavaScript method in a browser, which does not support the method.


Resource Description Framework

RDF is a W3C language for representing machine-readable propositional information on the Web.


Standard Generalized Markup Language

SGML is an ISO specification for defining markup languages. HTML4 has been defined with SGML. XML is a simplified successor of SGML. HTML5 is no longer SGML-based and has its own parsing rules.

Scalable Vector Graphics

SVG is a 2D vector image format based on XML. SVG can be styled with CSS and made interactive using JavaScript. HTML5 allows direct embedding of SVG content in an HTML document.


A slot is a name-value pair. In an object of an object-oriented program (for instance, in a Java object), a slot normally is a property-value pair. But in a JavaScript object, a slot may also consist of a method name and a method body or it may be a key-value pair of a map.



A platform-independent character set that includes almost all characters from most of the world's script languages including Hindi, Burmese and Gaelic. Each character is assigned a unique integer code in the range between 0 and 1,114,111. For example, the Greek letter π has the code 960. Unicode includes legacy character sets like ASCII and ISO-8859-1 (Latin-1) as subsets.

XML is based on Unicode. Consequently, the Greek letter π (with code 960) can be inserted in an XML document as π using the XML entity syntax. The default encoding of Unicode characters in an XML document is UTF-8, which uses only a single byte for ASCII characters, but three bytes for less common characters.

Uniform Resource Identifier

A URI is either a Uniform Resource Locator (URL) or a Uniform Resource Name (URN).

Uniform Resource Locator

A URL is a resource name that contains a web address for locating the resource on the Web.

Unified Modeling Language

The UML is an industry standard that defines a set of modeling languages for making various kinds of models and diagrams in support of object-oriented problem analysis and software design. Its core languages are Class Diagrams for information/data modeling, and Sequence Diagrams, Activity Diagrams and State Diagrams (or State Charts) for process/behavior modeling..

Uniform Resource Name

A URN refers to a resource without specifying its location.

User Agent

A user agent is a front-end web client program such as a web browser.



WebM is an open (royalty-free) web video format supported by Google Chrome and Mozilla Firefox, but not by Microsoft Internet Explorer and Apple Safari.

Web Hypertext Application Technology Working Group

The WHATWG was established in 2004 by former employees of Apple, Mozilla, and Opera who have been unhappy with the slow progress of web technology standardization due to W3C's choice to focus on the standardization of XHTML2. Led by Ian Hickson, they developed HTML5 and related JavaScript APIs in competition and collaboration with the W3C.

World Wide Web

The WWW (or, simply, "the Web") is a huge client-server network based on HTTP, HTML and XML, where web browsers (and other 'user agents'), acting as HTTP clients, access web server programs, acting as HTTP servers.

World Wide Web Consortium

The W3C is an international organization in charge of developing and maintaining web standards.


XML HTTP Request

The XML HTTP Request (XHR) API allows a JavaScript program to exchange HTTP messages with back-end programs. It can be used for retrieveing/submitting information from/to a back-end program without submitting HTML forms. XHR-based approaches have been subsumed under the acronym "AJAX" in the past.