Java script Chapter 1

🔹 1. What is JavaScript?

• JavaScript (JS) is a scripting language used to make web pages interactive and dynamic.
• It runs in the browser (client-side).
• Developed by Brendan Eich in 1995.

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🔹 2. Features of JavaScript

• Lightweight & Easy to learn
• Interpreted (no need for compilation)
• Event-driven & Object-based
• Platform independent
• Can manipulate HTML & CSS dynamically

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🔹 3. Uses of JavaScript

• Validating forms (e.g., checking empty fields)
• Creating animations, sliders, and popups
• Building interactive web applications
• Handling user events (click, mouseover, etc.)

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🔹 4. How to Add JavaScript to a Web Page

There are three ways:

A. Inline Script

<button onclick="alert('Hello!')">Click Me</button>

B. Internal Script

<script>
  alert("Welcome to my site!");
</script>

C. External Script

<script src="script.js"></script>

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🔹 5. Output Methods

• alert("message") – shows popup message
• console.log("message") – prints in console
• document.write("text") – writes on web page
• innerHTML – changes HTML content dynamically

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🔹 6. Comments

// Single-line comment
/* Multi-line comment */

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