function popen(urlstr,name,width,height,scrl,rsz)
{
   var top=(screen.height-height)/2;
   var left=(screen.width-width)/2;
   new_win = window.open(urlstr, name, 'toolbar=no, location=no, directories=no, status=no, scrollbars='+scrl+', resizable='+rsz+', menubar=no, width='+width+', height='+height+', top='+top+', left='+left+'');
   new_win.focus();
   return;
}