function newwin(url) {
  XX=(screen.width-640)/2;
  YY=(screen.height-480)/2; 
  subwinpopup=window.open(url,'subwin','width=640,height=480,resizable=yes,status=no,title=yes,toolbar=no,location=no,scrollbars=yes,screenX='+XX+',screenY='+YY+',left='+XX+',top='+YY);
subwinpopup.focus();
}

function gamewin(court,colour,level,title) {
  if (navigator.appName=="Microsoft Internet Explorer") {
    gamewinok(court,colour,level,title);
  } else {
    alert("Sorry, this game only works with Internet Explorer.");
  }

}

function gamewinok(court,colour,level,title) {
  document.forms.game.court.value=court;
  document.forms.game.colour.value=colour;
  document.forms.game.level.value=level;
  document.forms.game.title.value=title;
  XX=(screen.width-200)/2;
  YY=(screen.height-250)/2; 
  gamewinpopup=window.open('wingame.html','gamewin','width=200,height=250,resizable=no,status=no,title=yes,toolbar=no,location=no,scrollbars=no,screenX='+XX+',screenY='+YY+',left='+XX+',top='+YY);
gamewinpopup.focus();
}