function winopen(url) {
  var width=390;
  var height=350;
  var topx=(screen.height-height)/2;
  var leftx=(screen.width-width)/2;
  var fenstername=window.open(url,'fenstername','status=no,resizable=no,scrollbars=no,width='+width+',height='+height+',toolbar=no,screenx='+leftx+',screeny='+topx+',top='+topx+',left='+leftx);
  fenstername.focus();
}