JavaScript (JS) is a high-level, dynamic language standardized as ECMAScript. It runs in browsers, on servers (Node.js), and in many embedded runtimes.
Where JS runs
- Browser — DOM, events, fetch, Web APIs
- Node.js — files, HTTP servers, tooling (see Node.js track)
- Edge / workers — short-lived functions close to users
What it is not
Not Java (different language). Not only for animations—it's a general-purpose language with a huge ecosystem (npm).
Important interview questions and answers
- Q: JS vs Java?
A: Unrelated languages despite similar names. - Q: Is JS only front-end?
A: No—Node.js and edge runtimes use it on servers too.
Self-check
- List three places JavaScript runs.
- Why is npm relevant?
Tip: Re-run the playground code for what-is-javascript and tweak one line before the MCQs.
Interview prep
- JS vs Java?
Different languages despite the name.