function popup( a, width, height ) {
  var w = 800; if ( width < w ) w = width;
  var h = 600; if ( height < h ) h = height;

  var wnd = window.open( a.href,
               'popup',
               'width='+w+', height='+h+', scrollbars=yes, resizable=yes');
  wnd.resizeTo( w, h );
  wnd.focus();
}