Read the essentials on Javascript security...

General Topics
1

Hi malware fighters,

What is the importance of the same domain policy, and what browsers have what exemptions to this rule, and a lot other very import considerings to have at the back of your head, read online in these nice articles:
http://www.devarticles.com/c/a/JavaScript/JavaScript-Security/1/
and this: http://devedge-temp.mozilla.org/library/manuals/2000/javascript/1.3/guide/sec.html

Enjoy,

polonus

N.B. When you hit obfuscated JS you can nullify that encryption here online:
http://www.netdemon.net/haywyre/

2

Thanks for the links, Polonus.

For me, the second link was easier for me to read and understand.