HyperText Markup Language (HTML) is the standard markup language for documents designed to be displayed in a web browser. It defines the content and structure of web content. It is often assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScript. Web browsers receive HTML documents from a web server or from local storage and render the documents into multimedia web pages. HTML describes the structure of a web page semantically and originally included cues for its appearance. HTML elements are the building blocks of HTML pages. With HTML constructs, images and other objects such as interactive forms may be embedded into the rendered page. HTML provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links, quotes, and other items. HTML elements are delineated by tags, written using angle brackets.Browsers do not display the HTML tags but use them to interpret the content of the page. HTML can embed programs written in a scripting language such as JavaScript, which affects the behavior and content of web pages. The inclusion of CSS defines the look and layout of content. The World Wide Web Consortium (W3C), former maintainer of the HTML and current maintainer of the CSS standards, has encouraged the use of CSS over explicit presentational HTML since 1997.[2] A form of HTML, known as HTML5, is used to display video and audio, primarily using the element, together with JavaScript.
Cascading Style Sheets (CSS) is a style sheet language used for specifying the presentation and styling of a document written in a markup language such as HTML or XML (including XML dialects such as SVG, MathML or XHTML).[1] CSS is a cornerstone technology of the World Wide Web, alongside HTML and JavaScript.[2] CSS is designed to enable the separation of content and presentation, including layout, colors, and fonts.[3] This separation can improve content accessibility;[further explanation needed] provide more flexibility and control in the specification of presentation characteristics; enable multiple web pages to share formatting by specifying the relevant CSS in a separate .css file, which reduces complexity and repetition in the structural content; and enable the .css file to be cached to improve the page load speed between the pages that share the file and its formatting. Separation of formatting and content also makes it feasible to present the same markup page in different styles for different rendering methods, such as on-screen, in print, by voice (via speech-based browser or screen reader), and on Braille-based tactile devices. CSS also has rules for alternate formatting if the content is accessed on a mobile device.[4] The name cascading comes from the specified priority scheme to determine which declaration applies if more than one declaration of a property match a particular element. This cascading priority scheme is predictable. The CSS specifications are maintained by the World Wide Web Consortium (W3C). Internet media type (MIME type) text/css is registered for use with CSS by RFC 2318 (March 1998). The W3C operates a free CSS validation service for CSS documents.[5] In addition to HTML, other markup languages support the use of CSS including XHTML, plain XML, SVG, and XUL. CSS is also used in the GTK widget toolkit. Syntax CSS has a simple syntax and uses a number of English keywords to specify the names of various style properties. Style sheet Main article: Style sheet (web development) A style sheet consists of a list of rules. Each rule or rule-set consists of one or more selectors, and a declaration block. Selector "CSS class" redirects here. For non-CSS use of element classes in HTML, see class attribute (HTML). In CSS, selectors declare which part of the markup a style applies to by matching tags and attributes in the markup itself. Selector types Selectors may apply to the following: all elements of a specific type, e.g. the second-level headers h2 elements specified by attribute, in particular: id: an identifier unique within the document, denoted in the selector language by a hash prefix e.g. #id class: an identifier that can annotate multiple elements in a document, denoted by a dot prefix e.g. .classname (the phrase "CSS class", although sometimes used, is a misnomer, as element classes—specified with the HTML class attribute—is a markup feature that is distinct from browsers' CSS subsystem and the related W3C/WHATWG standards work on document styles; see RDF and microformats for the origins of the "class" system of the Web content model) elements depending on how they are placed relative to others in the document tree. Classes and IDs are case-sensitive, start with letters, and can include alphanumeric characters, hyphens, and underscores. A class may apply to any number of instances of any element. An ID may only be applied to a single element. Pseudo-classes Pseudo-classes are used in CSS selectors to permit formatting based on information that is not contained in the document tree. One example of a widely used pseudo-class is :hover, which identifies content only when the user "points to" the visible element, usually by holding the mouse cursor over it. It is appended to a selector as in a:hover or #elementid:hover. A pseudo-class classifies document elements, such as :link or :visited, whereas a pseudo-element makes a selection that may consist of partial elements, such as ::first-line or ::first-letter.[6] Note the distinction between the double-colon notation used for pseudo-elements and the single-colon notation used for pseudo-classes.
JavaScript (/ˈdʒɑːvəskrɪpt/), often abbreviated as JS, is a programming language and core technology of the Web, alongside HTML and CSS. 99% of websites use JavaScript on the client side for webpage behavior.[10] Web browsers have a dedicated JavaScript engine that executes the client code. These engines are also utilized in some servers and a variety of apps. The most popular runtime system for non-browser usage is Node.js. JavaScript is a high-level, often just-in-time compiled language that conforms to the ECMAScript standard.[11] It has dynamic typing, prototype-based object-orientation, and first-class functions. It is multi-paradigm, supporting event-driven, functional, and imperative programming styles. It has application programming interfaces (APIs) for working with text, dates, regular expressions, standard data structures, and the Document Object Model (DOM). The ECMAScript standard does not include any input/output (I/O), such as networking, storage, or graphics facilities. In practice, the web browser or other runtime system provides JavaScript APIs for I/O. Although Java and JavaScript are similar in name, syntax, and respective standard libraries, the two languages are distinct and differ greatly in design. History Creation at Netscape The first popular web browser with a graphical user interface, Mosaic, was released in 1993. Accessible to non-technical people, it played a prominent role in the rapid growth of the early World Wide Web.[12] The lead developers of Mosaic then founded the Netscape corporation, which released a more polished browser, Netscape Navigator, in 1994. This quickly became the most-used.[13] During these formative years of the Web, web pages could only be static, lacking the capability for dynamic behavior after the page was loaded in the browser. There was a desire in the flourishing web development scene to remove this limitation, so in 1995, Netscape decided to add a programming language to Navigator. They pursued two routes to achieve this: collaborating with Sun Microsystems to embed the Java language, while also hiring Brendan Eich to embed the Scheme language.[6] The goal was a "language for the masses",[14] "to help nonprogrammers create dynamic, interactive Web sites".[15] Netscape management soon decided that the best option was for Eich to devise a new language, with syntax similar to Java and less like Scheme or other extant scripting languages.[5][6] Although the new language and its interpreter implementation were called LiveScript when first shipped as part of a Navigator beta in September 1995, the name was changed to JavaScript for the official release in December.[6][1][16] The choice of the JavaScript name has caused confusion, implying that it is directly related to Java. At the time, the dot-com boom had begun and Java was a popular new language, so Eich considered the JavaScript name a marketing ploy by Netscape.[14]
Node.js is a cross-platform, open-source JavaScript runtime environment that can run on Windows, Linux, Unix, macOS, and more. Node.js runs on the V8 JavaScript engine, and executes JavaScript code outside a web browser. Node.js lets developers use JavaScript to write command line tools and for server-side scripting. The ability to run JavaScript code on the server is often used to generate dynamic web page content before the page is sent to the user's web browser. Consequently, Node.js represents a "JavaScript everywhere" paradigm,[6] unifying web-application development around a single programming language, as opposed to using different languages for the server- versus client-side programming. Node.js has an event-driven architecture capable of asynchronous I/O. These design choices aim to optimize throughput and scalability in web applications with many input/output operations, as well as for real-time Web applications (e.g., real-time communication programs and browser games).[7] The Node.js distributed development project was previously governed by the Node.js Foundation,[8] and has now merged with the JS Foundation to form the OpenJS Foundation. OpenJS Foundation is facilitated by the Linux Foundation's Collaborative Projects program.[9] History Ryan Dahl, creator of Node.js, in 2010 Rocket Turtle, the official mascot of Node.js since February 2024 Node.js was initially written by Ryan Dahl in 2009,[10] about 13 years after the introduction of the first server-side JavaScript environment, Netscape's LiveWire Pro Web.[11] The initial release supported only Linux and Mac OS X. Its development and maintenance was led by Dahl and later sponsored by Joyent.[12] Dahl criticized the limited capability of Apache HTTP Server to handle many (10,000+) concurrent connections, as well as the dominant programming paradigm of sequential programming, in which applications could block entire processes or cause the creation of multiple execution stacks for simultaneous connections.[13] Dahl demonstrated the project at the inaugural European JSConf on November 8, 2009.[14][15][16] Node.js combined Google's V8 JavaScript engine, an event loop, and a low-level I/O API.[17] In January 2010, a package manager was introduced for the Node.js environment called npm.[18] The package manager allows programmers to publish and share Node.js packages, along with the accompanying source code, and is designed to simplify the installation, update and uninstallation of packages.[17] In June 2011, Microsoft and Joyent implemented a native Windows version of Node.js.[19] The first Node.js build supporting Windows was released in July 2011. In January 2012, Dahl yielded management of the project to npm creator Isaac Schlueter.[20] In January 2014, Schlueter announced that Timothy J. Fontaine would lead the project.[21] In December 2014, Fedor Indutny created io.js, a fork of Node.js created because of dissatisfaction with Joyent's governance as an open-governance alternative with a separate technical committee. The goal was to enable a structure that would be more receptive to community input, including the updating of io.js with the latest Google V8 JavaScript engine releases, diverging from Node.js's approach at that time.[22] The Node.js Foundation, formed to reconcile Node.js and io.js under a unified banner, was announced in February 2015.[23] The merger was realized in September 2015 with Node.js v0.12 and io.js v3.3 combining into Node v4.0.[24] This merge brought V8 ES6 features into Node.js and started a long-term support release cycle.[25] By 2016, the io.js website recommended returning to Node.js and announced no further io.js releases, effectively ending the fork and solidifying the merger's success.[26] In 2019, the JS Foundation and Node.js Foundation merged to form the OpenJS Foundation. On September 6, 2023, Node.js 20.6.0 was released. The update brought the addition of built-in support for .env files, the unflagging of import.meta.resolve, the introduction of a new node:module API register for module customization hooks and a new initialize hook. Additionally, the module customization load hook now supports CommonJS, and Node.js C++ add-ons have gained experimental support for cppgc (Oilpan), which is a C++ garbage collection library for V8.[27]
Django (/ˈdʒæŋɡoʊ/ JANG-goh; sometimes stylized as django)[6] is a free and open-source, Python-based web framework that runs on a web server. It follows the model–template–views (MTV) architectural pattern.[7][8] It is maintained by the Django Software Foundation (DSF), an independent organization established in the US as a 501(c)(3) non-profit. Django's primary goal is to ease the creation of complex, database-driven websites. The framework emphasizes reusability and "pluggability" of components, less code, low coupling, rapid development, and the principle of don't repeat yourself.[9] Python is used throughout, even for settings, files, and data models. Django also provides an optional administrative create, read, update and delete interface that is generated dynamically through introspection and configured via admin models. Some well-known sites that use Django include Instagram,[10] Mozilla,[11] Disqus,[12] Bitbucket,[13] Nextdoor[14] and Clubhouse.[15] History Django was created in the autumn of 2003, when the web programmers at the Lawrence Journal-World newspaper, Adrian Holovaty and Simon Willison, began using Python to build applications. Jacob Kaplan-Moss was hired early in Django's development shortly before Simon Willison's internship ended.[16] It was released publicly under a BSD license in July 2005. The framework was named after guitarist Django Reinhardt.[17] Adrian Holovaty is a Romani jazz guitar player inspired in part by Reinhardt's music.[18] In June 2008, it was announced that a newly formed Django Software Foundation (DSF) would maintain Django in the future.[19]
PHP is a general-purpose scripting language geared towards web development.[8] It was originally created by Danish-Canadian programmer Rasmus Lerdorf in 1993 and released in 1995.[9][10] The PHP reference implementation is now produced by the PHP Group.[11] PHP was originally an abbreviation of Personal Home Page,[12][13] but it now stands for the recursive initialism PHP: Hypertext Preprocessor.[14] PHP code is usually processed on a web server by a PHP interpreter implemented as a module, a daemon or a Common Gateway Interface (CGI) executable. On a web server, the result of the interpreted and executed PHP code—which may be any type of data, such as generated HTML or binary image data—would form the whole or part of an HTTP response. Various web template systems, web content management systems, and web frameworks exist that can be employed to orchestrate or facilitate the generation of that response. Additionally, PHP can be used for many programming tasks outside the web context, such as standalone graphical applications[15] and drone control.[16] PHP code can also be directly executed from the command line. The standard PHP interpreter, powered by the Zend Engine, is free software released under the PHP License. PHP has been widely ported and can be deployed on most web servers on a variety of operating systems and platforms.[17] The PHP language has evolved without a written formal specification or standard, with the original implementation acting as the de facto standard that other implementations aimed to follow. W3Techs reports that as of 23 March 2024 (the four months after the PHP 8.3 release), PHP is used by 76.4% of all websites whose programming language could be determined, and 57.2% thereof use PHP 7 which is outdated and known to be insecure.[failed verification][18] History Rasmus Lerdorf, creator of PHP; and Andi Gutmans and Zeev Suraski, creators of the Zend Engine Early history PHP development began in 1993[9] when Rasmus Lerdorf wrote several Common Gateway Interface (CGI) programs in C,[19][20] which he used to maintain his personal homepage. He extended them to work with web forms and to communicate with databases, and called this implementation "Personal Home Page/Forms Interpreter" or PHP/FI.
Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let programmers write once, run anywhere (WORA),[16] meaning that compiled Java code can run on all platforms that support Java without the need to recompile.[17] Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of the underlying computer architecture. The syntax of Java is similar to C and C++, but has fewer low-level facilities than either of them. The Java runtime provides dynamic capabilities (such as reflection and runtime code modification) that are typically not available in traditional compiled languages. Java gained popularity shortly after its release, and has been a very popular programming language since then.[18] Java was the third most popular programming language in 2022 according to GitHub.[19] Although still widely popular, there has been a gradual decline in use of Java in recent years with other languages using JVM gaining popularity.[20] Java was originally developed by James Gosling at Sun Microsystems. It was released in May 1995 as a core component of Sun's Java platform. The original and reference implementation Java compilers, virtual machines, and class libraries were originally released by Sun under proprietary licenses. As of May 2007, in compliance with the specifications of the Java Community Process, Sun had relicensed most of its Java technologies under the GPL-2.0-only license. Oracle offers its own HotSpot Java Virtual Machine, however the official reference implementation is the OpenJDK JVM which is free open-source software and used by most developers and is the default JVM for almost all Linux distributions. As of March 2024, Java 22 is the latest version. Java 8, 11, 17, and 21 are previous LTS versions still officially supported. History See also: Java (software platform) § History Duke, the Java mascot James Gosling, the creator of Java, in 2008 James Gosling, Mike Sheridan, and Patrick Naughton initiated the Java language project in June 1991.[21] Java was originally designed for interactive television, but it was too advanced for the digital cable television industry at the time.[22] The language was initially called Oak after an oak tree that stood outside Gosling's office. Later the project went by the name Green and was finally renamed Java, from Java coffee, a type of coffee from Indonesia.[23] Gosling designed Java with a C/C++-style syntax that system and application programmers would find familiar.[24] Sun Microsystems released the first public implementation as Java 1.0 in 1996.[25] It promised write once, run anywhere (WORA) functionality, providing no-cost run-times on popular platforms. Fairly secure and featuring configurable security, it allowed network- and file-access restrictions. Major web browsers soon incorporated the ability to run Java applets within web pages, and Java quickly became popular. The Java 1.0 compiler was re-written in Java by Arthur van Hoff to comply strictly with the Java 1.0 language specification.[26] With the advent of Java 2 (released initially as J2SE 1.2 in December 1998 – 1999), new versions had multiple configurations built for different types of platforms. J2EE included technologies and APIs for enterprise applications typically run in server environments, while J2ME featured APIs optimized for mobile applications. The desktop version was renamed J2SE. In 2006, for marketing purposes, Sun renamed new J2 versions as Java EE, Java ME, and Java SE, respectively.
Structured Query Language (SQL) (pronounced S-Q-L; historically "sequel")[4][5] is a domain-specific language used to manage data, especially in a relational database management system (RDBMS). It is particularly useful in handling structured data, i.e., data incorporating relations among entities and variables. Introduced in the 1970s, SQL offered two main advantages over older read–write APIs such as ISAM or VSAM. Firstly, it introduced the concept of accessing many records with one single command. Secondly, it eliminates the need to specify how to reach a record, i.e., with or without an index. Originally based upon relational algebra and tuple relational calculus, SQL consists of many types of statements,[6] which may be informally classed as sublanguages, commonly: Data query Language (DQL), Data Definition Language (DDL), Data Control Language (DCL), and Data Manipulation Language (DML).[7] The scope of SQL includes data query, data manipulation (insert, update, and delete), data definition (schema creation and modification), and data access control. Although SQL is essentially a declarative language (4GL), it also includes procedural elements. SQL was one of the first commercial languages to use Edgar F. Codd's relational model. The model was described in his influential 1970 paper, "A Relational Model of Data for Large Shared Data Banks".[8] Despite not entirely adhering to the relational model as described by Codd, SQL became the most widely used database language.[9][10] SQL became a standard of the American National Standards Institute (ANSI) in 1986 and of the International Organization for Standardization (ISO) in 1987.[11] Since then, the standard has been revised multiple times to include a larger set of features and incorporate common extensions. Despite the existence of standards, virtually no implementations in existence adhere to it fully, and most SQL code requires at least some changes before being ported to different database systems.
MongoDB is a source-available, cross-platform, document-oriented database program. Classified as a NoSQL database product, MongoDB utilizes JSON-like documents with optional schemas. MongoDB is developed by MongoDB Inc. and current versions are licensed under the Server Side Public License (SSPL). MongoDB is a member of the MACH Alliance. History See also: MongoDB Inc. § History The American software company 10gen began developing MongoDB in 2007 as a component of a planned platform-as-a-service product. In 2009, the company shifted to an open-source development model and began offering commercial support and other services. In 2013, 10gen changed its name to MongoDB Inc.[5] On October 20, 2017, MongoDB became a publicly traded company, listed on NASDAQ as MDB with an IPO price of $24 per share.[6] On November 8, 2018 with the stable release 4.0.4, the software's license changed from AGPL 3.0 to SSPL.[7][8] On October 30, 2019, MongoDB teamed with Alibaba Cloud to offer Alibaba Cloud customers a MongoDB-as-a-service solution. Customers can use the managed offering from Alibaba's global data centers.[9]
React (also known as React.js or ReactJS) is a free and open-source front-end JavaScript library[4][5] for building user interfaces based on components. It is maintained by Meta (formerly Facebook) and a community of individual developers and companies.[6][7][8] React can be used to develop single-page, mobile, or server-rendered applications with frameworks like Next.js. Because React is only concerned with the user interface and rendering components to the DOM, React applications often rely on libraries for routing and other client-side functionality.[9][10] A key advantage of React is that it only rerenders those parts of the page that have changed, avoiding unnecessary rerendering of unchanged DOM elements. Notable features Declarative React adheres to the declarative programming paradigm.[11]: 76 Developers design views for each state of an application, and React updates and renders components when data changes. This is in contrast with imperative programming.[12] Components React code is made of entities called components.[11]: 10–12 These components are modular and reusable.[11]: 70 React applications typically consist of many layers of components. The components are rendered to a root element in the DOM using the React DOM library. When rendering a component, values are passed between components through props (short for "properties"). Values internal to a component are called its state.[13] The two primary ways of declaring components in React are through function components and class components.[11]: 118 [14]: 10
Angular (also referred to as "Angular 2+")[4] is a TypeScript-based, free and open-source single-page web application framework run on Node.js. It is led by the Angular Team at Google and by a community of individuals and corporations. Angular is a complete rewrite from the same team that built AngularJS. Angular ecosystem consists of a diverse group of over 1.7 million developers, library authors, and content creators.[5] Differences between Angular and AngularJS Architecture of an Angular application, services, and dependency injection Google designed Angular as a ground-up rewrite of AngularJS. Angular does not have a concept of "scope" or controllers; instead, it uses a hierarchy of components as its primary architectural characteristic.[6] Angular has a different expression syntax, focusing on "[ ]" for property binding, and "( )" for event binding[7] Modularity – much core functionality has moved to modules Angular recommends the use of Microsoft's TypeScript language, which introduces the following features: Static typing, including Generics Type annotations Dynamic loading Asynchronous template compilations Iterative callbacks provided by RxJS. Support to run Angular applications on servers. History Angular 2.0 was announced at the ng-Europe conference 22–23 October 2014.[8][9] The drastic changes in the 2.0 version created considerable controversy among developers.[10] On April 30, 2015, the Angular developers announced that Angular 2 moved from Alpha to Developer Preview.[11] Angular 2 moved to Beta in December 2015,[12] and the first release candidate was published in May 2016.[13] The final version was released on 14 September 2016.
TypeScript is a free and open-source high-level programming language developed by Microsoft that adds static typing with optional type annotations to JavaScript. It is designed for the development of large applications and transpiles to JavaScript.[6] Because TypeScript is a superset of JavaScript, all JavaScript programs are syntactically valid TypeScript, but they can fail to type-check for safety reasons. TypeScript may be used to develop JavaScript applications for both client-side and server-side execution (as with Node.js, Deno or Bun). Multiple options are available for transpilation. The default TypeScript Compiler can be used,[7] or the Babel compiler can be invoked to convert TypeScript to JavaScript. TypeScript supports definition files that can contain type information of existing JavaScript libraries, much like C++ header files can describe the structure of existing object files. This enables other programs to use the values defined in the files as if they were statically typed TypeScript entities. There are third-party header files for popular libraries such as jQuery, MongoDB, and D3.js. TypeScript headers for the Node.js library modules are also available, allowing development of Node.js programs within TypeScript.[8] The TypeScript compiler is itself written in TypeScript and compiled to JavaScript. It is licensed under the Apache License 2.0. Anders Hejlsberg, lead architect of C# and creator of Delphi and Turbo Pascal, has worked on the development of TypeScript.[9][10][11][12] History TypeScript was released to the public in October 2012, with version 0.8, after two years of internal development at Microsoft.[13][14] Soon after the initial public release, Miguel de Icaza praised the language itself, but criticized the lack of mature IDE support apart from Microsoft Visual Studio, which was not available on Linux and OS X at that time.[15][16] As of April 2021 there is support in other IDEs and text editors, including Emacs, Vim, WebStorm, Atom[17] and Microsoft's own Visual Studio Code.[18] TypeScript 0.9, released in 2013, added support for generics.[19] TypeScript 1.0 was released at Microsoft's Build developer conference in 2014.[20] Visual Studio 2013 Update 2 provides built-in support for TypeScript.[21] Further improvement were made in July 2014, when the development team announced a new TypeScript compiler, asserted to have a five-fold performance increase. Simultaneously, the source code, which was initially hosted on CodePlex, was moved to GitHub.[22] On 22 September 2016, TypeScript 2.0 was released, introducing several features, including the ability for programmers to optionally enforce null safety,[23] to mitigate what's sometimes referred to as the billion-dollar mistake. TypeScript 3.0 was released on 30 July 2018,[24] bringing many language additions like tuples in rest parameters and spread expressions, rest parameters with tuple types, generic rest parameters and so on.[25] TypeScript 4.0 was released on 20 August 2020.[26] While 4.0 did not introduce any breaking changes, it added language features such as Custom JSX Factories and Variadic Tuple Types.[26] TypeScript 5.0 was released on 16 March 2023 and included support for decorators.[27]