Wikipedia:WikiProject JavaScript/Glossary of JavaScript

This is an alphabetized glossary of terms pertaining to the programming language JavaScript, along with their meanings in the context of that language. JavaScript is the programming language of the Web. It is one of the 3 core web development technologies (the other two being HTML and CSS), and it is used on most web pages. Note that JavaScript is not related to Java; they are two distinctly different programming languages. Communication about JavaScript is highly jargonized. The following entries should help in understanding reading material about JavaScript, and serve as search terms for exploring the subject further.

A

• Ajax "(asynchronous JavaScript and XML)" – set of web development techniques using many web technologies on the client-side to create asynchronous Web applications. With Ajax, web applications can send data to and retrieve from a server asynchronously (in the background) without interfering with the display and behavior of the existing page. By decoupling the data interchange layer from the presentation layer, Ajax allows for web pages, and by extension web applications, to change content dynamically without the need to reload the entire page.
• Alert –
• Application development –
• Array –
  • Array literal –
  • Multi-dimensional array –
  • Array constructor –
• Asynchrony –
• Asynchronous JavaScript –
• Asynchronous module definition (AMD) –

B

• Best practice –
• Bookmarklet – technique of saving JavaScript within a bookmark or hyperlink, so that it can be executed by clicking on it. In many cases, the link can be dragged and dropped to the browser toolbar for easier access.

C

• Camel case –
• Cascading Style Sheets –
• Chakra – JavaScript engine developed by Microsoft for its Microsoft Edge web browser. It is a fork of the JScript engine used in Internet Explorer.
• Class –
• Client-side –
• Client-side JavaScript –
• Closure –
• Comment –
• CommonJS – project to create specifications for JavaScript beyond client-side scripting, to expand it into a more full-fledged language. For example, for writing server-side scripts and native desktop applications.
• Concatenation –
• CouchDB – server database that uses JavaScript as its query language.
• CSS – Cascading Style Sheets.

D

• Data type –
• Declarative programming –
• Document Object Model – the hierarchy (tree) produced by the browser of all the elements of a webpage. By processing the DOM via "methods" (functions stored as object properties, that is, the actions that can be performed on objects), JavaScript can dynamically change the page's HTML.
• DOM – Document Object Model
• Dynamic HTML – predecessor of Unobtrusive JavaScript.

E

• ECMAScript – the specification language upon which JavaScript is based. The terms "EMCAScript" and "JavaScript" are used interchangeably within the field. 'ES' has also been used as a prefix for shorthand names of versions of JavaScript:
  • 'ES5' – ECMAScript Fifth Edition, adopted in 2009.
  • 'ES6' / 'ES2015' – ECMAScript Sixth Edition, adopted in 2015.
  • 'ES7' / 'ES2016' – ECMAScript Seventh Edition, adopted in 2016.
  • 'ES2017' – ECMAScript Eighth Edition, adopted in 2017.
• Ecosystem –
• Etymology of JavaScript –
• Event-driven programming –
• Expression –

F

• Function –
  • Generator function –
• Function call –
• Functional programming –

G

• Generator function –
• Greasemonkey –

H

• HTML –
• HTML scripting – how locally executable scripts (such as those written in JavaScript) may be used in a web page.

I

• Imparative programming –

J

• JavaScript ecosystem –
• JavaScript engine  (list) – program or library which executes JavaScript code. A JavaScript engine may be a traditional interpreter, or it may utilize just-in-time compilation to bytecode in some manner. A JavaScript engine is most commonly included in web browsers, but is also a key component of JavaScript runtime environments and other software (such as database management systems).
  • Comparison of JavaScript engines
• JavaScript templating –
• JavaScript trademark –
• JS Foundation –
• JScript – essentially, "JavaScript for Internet Explorer". MicroSoft reverse engineered JavaScript and then named the implementation JScript to avoid infringing upon Sun's ownership of the JavaScript trademark. Since then, Microsoft has switched over to using the name JavaScript to refer to the implementation of JScript used in its Edge browser.
• JSGI –
• JSONP –

M

• Module –

N

• Nashorn – JavaScript engine developed in the Java programming language by Oracle. It is based on the Da Vinci Machine (JSR 292) and was released with Java 8. Its purposes are to enable embedding JavaScript in Java applications, and to develop standalone JavaScript applications.
• Node.js – open-source, cross-platform JavaScript runtime environment for executing JavaScript code server-side, to produce dynamic web page content before the page is sent to the user's web browser. Node.js is built upon the Chrome V8 JavaScript engine.
• NWJS –

O

• Object –
• Object orientation –
• Object-oriented programming in JavaScript –
• Object-oriented programming –
• Object –
• Operator –

P

• Promise –
• Prototype-based programming –

R

• Regex –
• Remote scripting –
• Reserved words in JavaScript –
• Rhino – JavaScript engine written fully in Java and managed by the Mozilla Foundation as open source software. It is intended to be used in server-side applications, hence there is no built-in support for the Web browser objects that are commonly associated with JavaScript.
• Runtime environment –

S

• Scope –
• Seed – interpreter and a library of the GNOME project to create standalone applications in JavaScript. It uses the JavaScript engine JavaScriptCore of the WebKit project.
• Server-side –
• Server-side JavaScript –
  • Comparison of server-side JavaScript solutions
• Server-side scripting –
• SpiderMonkey – the JavaScript engine in Firefox
• SquirrelFish – bytecode interpreter rewritten from JavaScriptCore.
• Statement –
• String –
• Structured programming –
• Subroutine – another name for "function".
• Switch statement –

T

• Tamarin – JavaScript engine still supported as part of Flash Player.
• Tampermonkey –
• Transpiler –

U

• Unobtrusive JavaScript –
• Userscript – JavaScript program written to modify web pages to augment browsing. They are installed in browsers by use of a userscript manager browser extension like Tampermonkey or Greasemonkey. A userscript feature is also available for registered users of Wikipedia, and can augment editing and viewing of that encyclopedia's pages.
• Userscript manager –

V

• V8 – JavaScript engine used in Google Chrome, Couchbase Server, MongoDB, and Node.js
• Vanilla JavaScript – jargon for "plain JavaScript", that is, JavaScript not extended by any frameworks or additional libraries. It even has its own prank promotion page, presenting it as the best JavaScript framework.
• Vanilla JS – same as "Vanilla JavaScript"
• Variable –