JavaScript terms
JavaScript has evolved from a scripting curiosity into a full-stack language powering browsers, servers, and everything in between. This category covers the language core — closures, prototypes, async patterns, the event loop, modern ES2024+ features — as well as runtime behaviour that trips up developers at every experience level. Understanding JavaScript deeply means fewer bugs and more confident code.
More on JavaScript
History
JavaScript was created in 1995 by Brendan Eich at Netscape Communications as a lightweight scripting language for web browsers, initially called Mocha and later LiveScript before being renamed JavaScript for marketing reasons. For over a decade, JavaScript remained primarily a client-side tool for DOM manipulation and form validation, with inconsistent implementations across browsers and limited standardization. The introduction of XMLHttpRequest in Internet Explorer 5 (1999) and subsequent AJAX adoption in the mid-2000s transformed JavaScript from a toy language into a serious platform for interactive web applications. The standardization of ECMAScript (ES5 in 2009) and major language improvements through ES2015 (ES6) and annual updates brought modern features like classes, promises, arrow functions, and modules, while the rise of Node.js (2009) extended JavaScript beyond browsers into server-side development. Today, JavaScript has evolved into a full-stack language with sophisticated tooling (bundlers, frameworks, type systems), widespread use in both frontend and backend, and a mature ecosystem that makes it one of the most widely-used programming languages in the world.
Key concepts
- JavaScript Closures
- JavaScript Event Loop
- Hoisting — var
- let
- const and function
- Promises & Promise Chaining
- DOM Manipulation
- ES Modules (import/export)
- Async Error Handling (try/catch + Promise)
- Type Coercion Gotchas (== vs ===)
Best references
-
MDN Web Docs — JavaScript Authoritative reference for all JavaScript APIs, language features, and DOM standards. Covers every term in this category with examples and browser compatibility.
-
ECMAScript Language Specification (ECMA-262) The official standard defining JavaScript syntax, types, and built-in objects. Essential for understanding the specification behind language features like async/await, modules, and error handling.
-
You Don't Know JS Yet (Kyle Simpson) Deep, practical treatment of closures, scope, hoisting, prototypes, async patterns, and type coercion—foundational concepts underpinning many glossary terms.
-
JavaScript.info Comprehensive tutorial covering modern JavaScript from fundamentals through advanced topics like Promises, Generators, and the Event Loop with interactive examples.
-
Web APIs — MDN Complete reference for browser APIs (Fetch, Canvas, Geolocation, Streams, MutationObserver, etc.) covered extensively in this category.
Typed relationships here
Edges touching a JavaScript term.
- Web Components Applies ARIA Roles & Attributes 5d
- Web Components Leverages Custom Events & EventTarget API 5d
- Axios — HTTP Client for PHP APIs Often seen in async / await in JavaScript 6d
- Client-Side Sanitisation Mitigates CSS Injection & Data Exfiltration via Stylesheets Jun 16
- Error.cause — Error Chaining Often seen in Async Error Handling (try/catch + Promise) Jun 14
JavaScript Generators
ES2015
1