function pop(item, w, h)
{
        var winleft;
        var winup;
    
        if (document.all || document.layers) {
            winleft = (screen.availWidth - w) / 2;
            winup  = (screen.availHeight - h) / 2;
	} else {
            winleft = (screen.width - w) / 2; 
            winup = (screen.height - h) / 2; 
        }
        
        var popup = window.open(item, 'Apparat', 'top='+winup+',left='+winleft+',toolbar=no, status=no,resizable=no,width='+w+',height='+h+',scrollbars=no');
        popup.focus();
        return false;
        
}

function resizeWindow(w,h)
{
    if (document.all || document.layers) {
        winleft = (screen.availWidth - w) / 2;
        winup  = (screen.availHeight - h) / 2;
    } else {
        winleft = (screen.width - w) / 2; 
        winup = (screen.height - h) / 2; 
    }
    self.moveTo(winleft,winup);
    self.resizeTo(w,h);
}