function newwindow(width,height,url,title) 
{
    var new_window;
    var posleft = (screen.width - width) / 2;
    var postop  = (screen.height - height) / 2;
    
    new_window = window.open(url,title,'width='+width+',height='+height+',left='+posleft+',top='+postop+',resizeable=yes,scrollbars=yes,status=yes');
    new_window.focus();
}