What is JavaScript?
A quick tour of JavaScript: where it came from, what makes it tick, and why it runs most of the web.
Sources
- [1]JavaScriptwikipedia
- [2]JavaScript syntaxwikipedia
- [3]JavaScript XMLwikipedia
- [4]Semantics and Security Issues in JavaScriptarxiv
- [5]CodeCity for (and by) JavaScriptarxiv
The short version
JavaScript (JS) is a programming language and one of the three core technologies of the web, sitting next to HTML and CSS [Source 1]. If you've ever clicked a button on a page and watched something happen without a full reload, that was almost certainly JavaScript doing the work.
Brendan Eich created it in 1995. Today it's maintained by Ecma International's TC39 committee, with the related Web APIs handled by W3C and WHATWG [Source 1]. As of 2025, it's the most widely used programming language on GitHub [Source 1].
Where it runs
Originally JavaScript was the browser's scripting language, full stop. That's still its home turf, but it's spread well beyond that. It's popular enough that researchers have built tools like JSCity, a software visualization tool written in JavaScript that runs directly in the browser without any install step [Source 5].
Syntax, briefly
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