HTML 5 (formerly spelled HTML5[a]) is a markup language used for structuring and presenting content on the World Wide Web. It is the fifth and current major version of the HTML standard, and subsumes XHTML. It currently exists in two standardized forms: HTML 5.2 Recommendation[4] by the World Wide Web Consortium (W3C, a broad coalition of organizations), intended primarily for Web content developers; and HTML Living Standard [5] by WHATWG (a small consortium of four browser vendors), intended primarily for browser developers, though it also exists in an abridged Web developer version.[6] There are minor conflicts between the two groups' specifications. HTML 5 was first released in public-facing form on 22 January 2008,[7] with a major update and "W3C Recommendation" status in October 2014.[2][8] Its goals are to improve the language with support for the latest multimedia and other new features; to keep the language both easily readable by humans and consistently understood by computers and devices such as Web browsers, parsers, etc., without XHTML's rigidity; and to remain backward-compatible with older software. HTML 5 is intended to subsume not only HTML 4, but also XHTML 1 and DOM Level 2 HTML;[9] the HTML 4 and XHTML specs were announced as superseded by HTML 5.2 on 27 March 2018.[10]
Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation of a document written in a markup language like HTML.[1] CSS is a cornerstone technology of the World Wide Web, alongside HTML and JavaScript.[2] CSS is designed to enable the separation of presentation and content, including layout, colors, and fonts.[3] This separation can improve content accessibility, 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, and reduce complexity and repetition in the structural content. 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 style rule applies if more than one rule matches a particular element. This cascading priority scheme is predictable.
Node.js is an open-source, cross-platform JavaScript run-time environment that executes JavaScript code outside of a browser. Typically, JavaScript is used primarily for client-side scripting, in which scripts written in JavaScript are embedded in a webpage's HTML and run client-side by a JavaScript engine in the user's web browser. Node.js lets developers use JavaScript to write Command Line tools and for server-side scripting—running scripts server-side to produce 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, rather than different languages for server side and client side scripts.