Javascript User Defined Settings Question

Ok... basically right now I'm just trying to see if this is doable with javascript.

Hypothetical situation:

We have a website with two sections.
Section1: A photo gallery w/ 10 pictures
Section2: Slideshow

I would like to allow my user to select their favorite pictures from the 10 in the gallery. When they click the slideshow link, the slideshow would only display the certain images the user chose while viewing the gallery. Included would be functionality for the user to add and remove images from the slideshow at will.

Is this possible to do with just javascript?

Thanks for any leads.

It's doable...
But to implement it... not quite a walk in the park I say... :p