var showwindow;

function shownewwindow(windowName, link, height, width) {
  shownewwindow(windowName, link, height, width, 50, 50);
}

function shownewwindow(windowName, link, height, width, left, top) {
  var xpos = ((window.screen.width-height)/2);
  var ypos = ((window.screen.height-width)/2);
  closeWindow(showwindow);
  showwindow = window.open(link,windowName,"height=" + height + ",width=" + width + ",resizable=yes,left=" + left + ",top=" + top + ",screenX=" + xpos + ",screenY=" + ypos + ",status=no,scrollbars=yes,menubar=no,toolbar=no,location=no");
  
  showwindow.focus();
}

function closeWindow(theWindow)
{
        if (theWindow) {
           if (!theWindow.closed)
            {
               theWindow.close();
            }
         }
}

function closePopUpWindows()
{
        closeWindow(showwindow);
}