var has_focus = 0;
var browser_version = parseInt (navigator.appVersion);
if (browser_version >= 3) { has_focus   = 1; }
if (navigator.appName == "Microsoft Internet Explorer") { if (browser_version > 3) has_focus = 1; }

function popup (url, breite, hoehe)
{
  window_name = url.substring ((url.length-9), (url.length-5));
  window_params = 'toolbar=0,location=0,left=100,top=100,directories=0,status=0,menubar=0,resizable=1,scrollbars=1,width='+breite+',height='+hoehe;
  this_popup = open (url + '?' + window_name, window_name, window_params);
  if (has_focus) this_popup.focus();
}