Introducing JavaScript

• HTML is the content.
• CSS is the presentation.
• JavaScript is the behavior (makes your pages 'interactive' for the user).

What can you do with JavaScript? Here are just a things you can do...

1. Use JavaScript to respond to events (event handling).
   
   
2. Use JavaScript to validate user input.
   
   Enter a number:   Please enter a NUMBER
3. Use JavaScript for animation.
   
   
4. Use JavaScript to fetch data from a web server.
   (Note: This code is not actually fetching data from a server, it's just a simulation.)
   
   
5. Use JavaScript to control the elements in an HTML page.