page-up and page-down key on Mac? [duplicate]

Possible Duplicate:
How do I type Home on a MacBook Pro?

I am using a MacBook Pro running Mac OS X 10.5. I am new to this development environment, and previously worked on Windows.

I am wondering what is the page-up and page-down key on the Mac? My MacBook Pro seems to not have these two keys on the keyboard.

Thanks in advance.

Short answer: fn+up arrow for page up, fn+down arrow for page down.

More than you asked for:

On all browsers I have installed (Safari, Firefox & Chrome), I tend to use space and shift+space more often.

External keyboards (with built-in page up and page down keys) work well, too.