docs(js): add JavaScript language documentation

Author: m2y11138

docs/docs/languages/javascript.mdx

@@ -1,3 +1,85 @@
 # JavaScript
 
-TODO...
+[JavaScript](https://developer.mozilla.org/docs/Web/JavaScript) is a versatile, interpreted programming language that powers the dynamic behavior on most websites. 
+
+LiveCodes runs JavaScript natively in the browser.Since JavaScript runs in the browser, it has a host environment with access to the DOM and other Web APIs, but it does not have Node.js features such as the file system or process information.
+
+## Demo
+
+import LiveCodes from '../../src/components/LiveCodes.tsx';
+
+export const params = {
+  template:"Javascript",
+  console:"open"
+};
+
+<LiveCodes params={params}></LiveCodes>
+
+## Usage
+
+LiveCodes executes JavaScript directly in the browser.
+
+You can use it to test and demonstrate JavaScript code that interacts with the DOM, fetch APIs, or manipulate HTML elements dynamically.
+
+### Loading Modules
+
+Most of the core functionality in JavaScript is available directly in the browser without any additional installation.
+
+#### Standard Library
+
+JavaScript provides a standard set of built-in objects and functions which are available directly in the browser.
+
+#### External Packages
+To use additional functionality not included in the core language, you can import external packages (libraries) from CDN links.
+
+```js
+import _ from 'https://cdn.jsdelivr.net/npm/lodash-es@4.17.21/lodash.min.js';
+
+const arr = [1, 2, 3, 4, 5];
+console.log(_.shuffle(arr)); // shuffle the array
+```
+
+If you use JavaScript syntax extensions like JSX or JavaScript libraries/frameworks, you can select them directly in the programming language selection.
+
+## Language Info
+
+### Name
+
+`Javascript`
+
+### Aliases
+
+`js`,`node`,`ecmascript`
+
+### Extensions
+
+`js`
+
+### Editor
+
+`script`
+
+### Compiler
+
+JavaScript runs natively in the browser — no compilation is required.
+
+### Version
+
+Depends on the browser's JavaScript engine and its supported ECMAScript features.
+
+## Code Formatting
+
+Using [Prettier](https://prettier.io/) for code Formatting.You can format your code when saving the project, but you need to manually enable “Format on Save” in the settings.
+
+## Live Reload
+
+JavaScript code automatically reloads and executes when edited, allowing for real-time feedback.
+
+## Starter Template
+
+https://livecodes.io/?template=Javascript
+
+## Links
+
+- [JavaScript](https://developer.mozilla.org/en-US/docs/Web/JavaScript)
+- [Web API](https://developer.mozilla.org/en-US/docs/Web/API)