need help with javascript injections

I have read many and many articles and tutorials on how to do these. I cannot seem to get it to work though when i type

Javascript:alert(document.cookies)

all i get is a dialouge box that says "undefined". What does that mean? and how do i actually view the cookies. Now plz forgive my ignorance because im still newb to javascript but im getting better. Any help would be appriciated

"undefined" pops up when there's a syntax error,you had

javascript:alert(document.cookies)

take the s out of cookies, so it's

javascript:alert(document.cookie)

another way to view cookies is by using the; javascript:document.cookie

yo can also edit JS cookies with the simple command:

javascript:void(document.cookie="FieldA=FieldB" );alert(document.cookie);

Substitute the field for w/e the purpose. ex: User=Pass, Authorized=Yes

google some other forms of js injections

Use the firefox extension Add & Edit Cookies - Cookies Editor