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JavaScript · Module 1 of 10

What JavaScript does

JavaScript makes web pages interactive and also runs on servers with Node.js.

📖 Key ideas

  1. HTML builds the page, CSS styles it, JavaScript makes it react to users.
  2. Every browser has a JavaScript engine; open DevTools (F12) and use the Console to try code.
  3. console.log("Hi") prints to the console.
  4. Node.js runs JavaScript outside the browser, for servers and tools.
  5. Statements usually end with a semicolon (optional but recommended).
💡 Real-life example: If a website is a car, HTML is the body, CSS is the paint, and JavaScript is the engine that makes it move.
console.logPrints a message to the console
DevToolsBrowser tools to inspect and debug
Node.jsRuns JavaScript on servers
EngineProgram that runs JavaScript, like V8