function fullscreen(url){
  var ie = navigator.appVersion.indexOf("MSIE");
  var ie4 = (ie>0) && (parseInt(navigator.appVersion.substring(ie+5, ie+6)) >= 4);
  var nn = navigator.appName.lastIndexOf("Netscape");
  var nn4 = (nn >= 0) && (parseInt(navigator.appVersion.substring(0,2)) >= 4);

  if (nn4){
    var newwindow;
    var opt = "scrollbars,width=" + window.screen.width + ",height=" + window.screen.height;
    newwindow = window.open(url, "newwindow", opt);
    newwindow.moveTo(0,0);
    newwindow.focus();
  } else if (ie4){
    window.open(url, "screen", "fullscreen=yes");
  } else{
    location.href=url;
  }
}