var imppopheight=290;
  var imppopwidth=440;

  function openImpWindow(pageToLoad, winName, center) {
  xposition=0; yposition=0;
  if ((parseInt(navigator.appVersion) >= 4 ) && (center)){
  xposition = (screen.width - imppopwidth) / 2;
  if (xposition < 480) xposition = 480;
  yposition = (screen.height - imppopheight) / 2;
  }
  args = "width=" + imppopwidth + ","
    + "location=0,"
    + "menubar=0,"
    + "resizable=yes,"
    + "status=0,"
    + "titlebar=0,"
    + "toolbar=0,"
    + "scrollbars=yes,"
    + "height=" + imppopheight + ","
    + "screenx=" + xposition + ","  //NN
    + "screeny=" + yposition + ","  //NN
    + "left=" + xposition + ","    //IE
    + "top=" + yposition;          //IE
  var imppopwin=window.open(pageToLoad,winName,args);
  imppopwin.focus();
 }