var p_win = new Array();

function openpreview(startpage, windowName, windowOption) {
  p_win[windowName] = window.open(startpage, windowName, windowOption);
  p_win[windowName].focus();
  setTimeout("p_win['"+windowName+"'].focus()",200);
}

function openorfocus(startpage, windowName, windowOption) {
  if ( typeof( p_win[windowName] ) != 'undefined' ) {
    if (!p_win[windowName].closed) {
      p_win[windowName].focus();
      p_win[windowName].location.href = startpage;
    }
    else
      openpreview(startpage, windowName, windowOption);
  }
  else
    openpreview(startpage, windowName, windowOption);
}

function openorfocus_callback(href) {
  openorfocus('/callback.html','callback','resizable=no,scrollbars=yes,status=no,location=no,menubar=no,toolbar=no,width=410,height=400');
}