function checkPlugin(plgIn) { //v4.0
  var ok=false;
  with (navigator) if (appName.indexOf('Microsoft')==-1 || (plugins && plugins.length)) {
    ok=(plugins && plugins[plgIn]);
  } else if (appVersion.indexOf('3.1')==-1) { //not Netscape or Win3.1
    if (plgIn.indexOf("Flash")!=-1 && window.MM_flash!=null) ok=window.MM_flash;
    else if (plgIn.indexOf("Director")!=-1 && window.MM_dir!=null) ok=window.MM_dir;
    else ok=true; }
  if (!ok) {
  return false;
 }
 else {
  return true;
 }
}