function openSlideshow(slideshow)
{
    var w=750;
    var h=600;
    var x=screen.width/2-w/2;
    var y=screen.height/2-h/2;
    window.open('slideshows/'+slideshow+'.htm','slideshow','status=no,toolbar=no,location=no,menubar=no,directories=no,resizable=no,height='+h+',width='+w).moveTo(x,y);
}