function detectFlash() {  
  // If navigator.plugins exists...
  if (navigator.plugins) {
    // ...then check for flash 2 or flash 3+.
    if (navigator.plugins["Shockwave Flash 2.0"]
        || navigator.plugins["Shockwave Flash"]) {

      // Some version of Flash was found. Time to figure out which.
      
      // Set convenient references to flash 2 and the plugin description.
      var isVersion2 = navigator.plugins["Shockwave Flash 2.0"] ? " 2.0" : "";
      var flashDescription = navigator.plugins["Shockwave Flash" + isVersion2].description;

      var flashVersion = parseInt(flashDescription.substring(16));

      flash2Installed = flashVersion == 2;    
      flash3Installed = flashVersion == 3;
      flash4Installed = flashVersion == 4;
      flash5Installed = flashVersion == 5;
      flash6Installed = flashVersion == 6;
      flash7Installed = flashVersion == 7;
      flash8Installed = flashVersion == 8;
      flash9Installed = flashVersion >= 9;
    }
  }
  
  // Loop through all versions we're checking, and
  // set actualVersion to highest detected version.
  for (var i = 2; i <= maxVersion; i++) {  
    if (eval("flash" + i + "Installed") == true) actualVersion = i;
  }
  
  if(navigator.userAgent.indexOf("WebTV") != -1) actualVersion = 4;  
  
  // If the user has a new enough version...
  if (actualVersion >= requiredVersion) {
    // ...then we'll redirect them to the flash page, unless we've
    // been told not to redirect.
    if (useRedirect) {
      // Need javascript1.1 to do location.replace
      if(jsVersion > 1.0) {
        // It's safe to use replace(). Good...we won't break the back button.
        window.location.replace(flashPage);  
      } else {
        // JavaScript version is too old, so use .location to load
        // the flash page.
        window.location = flashPage;
      }
    }
    
    hasRightVersion = true;                
  } else {  
    if (useRedirect) {
      // Do the same .replace() call only if js1.1+ is available.
      if(jsVersion > 1.0) {
        window.location.replace((actualVersion >= 2) ? upgradePage : noFlashPage);
      } else {
        window.location = (actualVersion >= 2) ? upgradePage : noFlashPage;
      }
    }
  }
}
detectFlash();  // call our detector now that it's safely loaded.