function popup(mylink, windowname, lWidth, lHeight)
{

  if (lWidth == undefined ) {
    lWidth = 600;
  }
  
  if (lHeight == undefined) {
    lHeight = 600;
  }
  
  if (! window.focus)return true;
  var href;
  if (typeof(mylink) == 'string')
     href=mylink;
  else
     href=mylink.href;
  window.open(href, windowname, 'width='+lWidth+',height='+lHeight+',location=no,scrollbars=yes');
  return false;
}