Pop up

<a href="#" onclick="window.open('http://www.jubii.dk','hej', 'status=no,toolbar=no,location=no,menu=no,resizeable=no scrollbars=yes')">Åben</a>

eller

var popUpWin=0;
function popUpWindow(URLStr, left, top, width, height) {
  if(popUpWin) {
    if(!popUpWin.closed) popUpWin.close();
  }
  popUpWin = open(URLStr, 'popUpWin', 'toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=no,copyhistory=yes,width='+width+',height='+height+',left='+left+', top='+top+',screenX='+left+',screenY='+top+'');
}

og

<a href="#" onClick="popUpWindow('side.html','left=0,top=0,width=400,height=400');return false;">link</a>

med bestemt størrelse:

<a href="#" onclick="window.open('http://www.jubii.dk','hej', 'height=300, width=400, status=no,toolbar=no,location=no,menu=no,resizeable=no scrollbars=yes')">Åben</a>