var windows = new Array();

function newWindow(url,wname,w,h) {
  for (wi in windows) 
    if (!windows[wi].closed) windows[wi].close();
  return window.open(url,wname,
      "width=" + w + ",height=" + h + ",left=200,top=15,titlebar=no");
}

function createWindow(url,wname,w,h) {
  windows[wname] = new newWindow(url,wname,w,h);
}