var newwin;
var opencount;

function openup()
{
  opencount = 0;
}

function closedown()
{
  if ((opencount > 0) && !newwin.closed)
    {
      newwin.close();
    }
}

function openwindow(url, width, height)
  {
    if (opencount > 0)
      {
	newwin.close();
      }
    newwin = window.open(url, "popup", "status=0,toolbar=0,location=0,menubar=0,directories=0,resizable=1,scrollbars=1,width=" + width + ",height=" + height);
    opencount++;
  }