📦 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.
Table of Contents
Hello, JavaScript!
Let's write your first JavaScript program:
<script>
console.log("Hello, JavaScript!");
</script>Output...
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!