ok i've been working on my site, and with css pseudo-class

a.browse:link
a.browse:visited
a.browse:hover
a.browse:active

here's how i set my code on css... realising that hover must come after link and visited and active after hover!

a.browse:link, a.browse:visited{blah blah blah}
a.browse:hover{blah}
a.browse:active{blah}

i don't really see the active effects, which makes me wonder what does it really do? or when does it happen?

does active occur between the clicking and the starting of the next page reload?

You have them in the correct order (link/visited/active/hover)

Active does "do something." It gives the link with focus a different look if you've defined it in your CSS rules.

To see what "active" state (with foucs) looks like, use your tab key and tab down through your links. As you tab through them, the link gets focus and should reflect whatever CSS rules you've applied to that link state.