Scrollbar i funktion

Hej eksperter,

er der nogen der gider vise mig hvordan man kan få scrollbar med i sit pop-up vindue i det her script?

function popup(url,name,win_height,win_width) {
    pos_horizon = ((screen.width/2)-(win_width/2));
    pos_vertical = ((screen.height/2)-(win_height/2));
window.open(url,name,"width="+win_width+",height="+win_height+",top="+pos_vertical+",left="+pos_horizon);
    }

tak
/Morten