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.


Document Object Model

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 a 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.



PNG stands for Portable Network Graphics, which is a 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.



RDF stands for Resource Description Framework, which is a W3C language for representing machine-readable propositional information on the web.



SGML stands for Standard Generalized Markup Language, which 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.


SVG stands for Scalable Vector Graphics, which 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 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.


URI stands for Uniform Resource Identifier, which is either a URL or a URN.


URL stands for Uniform Resource Locator, which is a resource name that contains a web address for locating the resource on the web.


URN stands for Uniform Resource Name, which 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 (royatly-free) web video format supported by Google Chrome and Mozila Firefox, but not by Microsoft Internet Explorer and Apple Safari.


The Web Hypertext Application Technology Working Group (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.


W3C stands for World Wide Web Consortium, which is an international organization in charge of developing and maintaining web standards.