> For the complete documentation index, see [llms.txt](https://riteshs4hu.gitbook.io/infosec-notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://riteshs4hu.gitbook.io/infosec-notes/language/javascript-js.md).

# JavaScript (JS)

## What is JavaScript?

JavaScript (JS) is an **interpreted programming language** to create **dynamic and interactive** web pages. It is one of the core technologies of web development, alongside **HTML** (structure) and **CSS** (style).

* **Loosely Typed** – You don’t need to declare variable types explicitly. JS determines them at runtime.
* **Interpreted Language** – Runs directly in the browser without needing compilation.
* **Event-driven** – Executes code responding to user actions (clicks, keypresses, etc.).
* **Single-Threaded with Asynchronous Capabilities** – Uses the **event loop** to handle multiple operations efficiently.