This document provides an introduction to JavaScript and the jQuery library. It discusses some common JavaScript pitfalls like boolean type conversions and issues with function declarations. It then explains how jQuery helps solve browser compatibility issues and makes development faster by providing DOM manipulation, CSS selection, event handling, AJAX capabilities and plugins. jQuery's motto of "write less do more" is explained through examples of how it simplifies tasks like DOM access, event handling, and AJAX calls through chaining methods. Ways to include JavaScript in Drupal are also briefly covered.

1. Introduction to the
wonderful world of JS.
• JavaScript - pitfalls and gotchas
• jQuery - a JavaScript library
• Examples and questions

2. Jakob Torp
• @googletorp
• Work in Reveal IT - mostly Drupal
developer/consultant.
• Drupal 1.3 years

3. JavaScript
pitfalls and gotchas

4. JavaScript OO
programming language
• Object oriented.
• No relations to Java. (LiveScript)
• Purpose is to make the browser interactive.
• Created by NetScape in 2 weeks!
• Reverse engineered by Microsoft. (browser war)
• Official name: ECMAScript.

5. JavaScript happens in
the browser.

6. Boolean
type conversions

7. Object declarations.
Last comma causes syntax error in IE

8. Function declarations.

9. Functions can be
passed as variables.

10. Functional scope

11. Closure.

12. jQuery
a JavaScript library

13. Why use a library?
• Development framework like Drupal.
• Reuse code - faster development.
• Good documentation.
• Help solve browser issues.
• Help optimising your code.

14. jQuery motto
“write less do more”
• DOM - Document Object Model.
• CSS selection - fast and easy (Sizzle)
• Event handlers - click, focus etc.
• AJAX & animations
• Plugins - works like a Drupal module.

15. DOM

16. CSS selection
VS:

17. Events & eventhandlers
• Events - user interaction:
click, focus, blur ect.
• Event-handlers - Execute code for specific
events. (function).

18. jQuery chaining
jQuery returns jQuery

19. Ajax simplified

20. jQuery plugins
Flot module

21. drupal_add_js()
• Add your own js file on a given page.
• Add PHP variables to the global Drupal
variable.
• Possible to set scope and other options.
• Edge case, drupal_get_js()

22. Examples & questions