function window_popup(url, w, h, name, scroll, resize, tool, location)  
{
    var winleft = (screen.width - w) / 2; 
    var wintop = (screen.height - h) / 2;
    var winprops = "height="+h+",width="+w+",top="+wintop+",left="+winleft+",scrollbars="+scroll+",resizable="+resize+",toolbar="+tool+",location="+location;
    var win = window.open(url, name, winprops);
    if(window.focus) 
    {
        win.focus();
    }
}