📦 Lesson 2: JavaScript Variables & Data Types
⏱️ Estimated time: 20 minutes | Difficulty: Beginner
Storing Data
Variables are containers for storing data values. In JavaScript, we use let,
const, or var to declare variables.
Hello, JavaScript!
Let's write your first JavaScript program:
<script>
console.log("Hello, JavaScript!");
</script>Where to Put JavaScript
In HTML Head
<head>
<script>
console.log("Runs first");
</script>
</head>In HTML Body
<body>
<script>
console.log("Runs after HTML loads");
</script>
</body>External File
<script src="app.js">
</script>Using the Console
The console is where JavaScript displays messages. Open it:
- Right-click on a webpage → "Inspect" (or press F12)
- Click the "Console" tab
- You'll see messages from JavaScript
Your First Real Program
<!DOCTYPE html>
<html>
<head>
<title>My First JavaScript</title>
</head>
<body>
<h1>Welcome!</h1>
<script>
console.log("JavaScript is running!");
console.log("I can write messages here");
console.log("This is awesome!");
</script>
</body>
</html>Output in console:
JavaScript is running!
I can write messages here
This is awesome!