Audiobook M3U Generator

@script jscript
function zeroPad(num)
{
  var numZeropad = num + '';
  while(numZeropad.length < 2){
  numZeropad = "0" + numZeropad;
}
return numZeropad;
}
function numberCDS(CD){
  var getCDNumber = zeroPad(CD);
return getCDNumber;
}
function isAudio(extension)
{
  switch (extension.toLowerCase()){
  case '.mp3':
  case '.wav':
  case '.ogg':
  case '.m4v':
  case '.flac':
  case '.wma':
      return true;
    }
  return false;
}
function OnClick(ClickData)
{
      var objCmd = ClickData.Func.Command;
      var allFiles = objCmd.sourcetab.files;
      var objEnum = new Enumerator(allFiles);
      if (!objEnum.atEnd())
      {
              // build an array of the files so we can sort it
              var objFiles = new Array();
              i = 0;
              while (!objEnum.atEnd())
              {
                    objFiles[i] = objEnum.item();
                    if (isAudio(objFiles[i].ext) == false)
                    {
                      objFiles.splice (i, 1);
                    }
                    ++i;
                    objEnum.moveNext();
              }
      objFiles.sort();
      ClickData.func.command.ClearFiles();
      audiobookFolderName = objCmd.sourcetab.path.filepart;
      var audiobookFolderPath = objCmd.sourcetab.path;
      var fso, f1;
      var ForWriting = 2;
      var totalNumberOfFiles = objCmd.sourcetab.stats.files;
      var Dopus = DOpus.CreateCommand;
      var dlg = Dopus.Dlg;
      dlg.window = DOpus.Listers(0);
      dlg.message = "Split audiobook every nth file:";
      dlg.title = "Audiobook M3U Generator";
      dlg.buttons = "OK|Cancel";
      dlg.choices = DOpus.NewVector("2", "3", "4", "5", "6", "7", "8", "9", "10")
      dlg.selection = 0
      ret = dlg.show;
      if (ret == 0)
      {
           return;
      }
      var chosenOutput = dlg.choices(dlg.selection);
      switch (chosenOutput){
      case '2':
      var chosenNumber = 2;
      break;
      case '3':
      var chosenNumber = 3;
      break;
      case '4':
      var chosenNumber = 4;
      break;
      case '5':
      var chosenNumber = 5;
      break;
      case '6':
      var chosenNumber = 6;
      break;
      case '7':
      var chosenNumber = 7;
      break;
      case '8':
      var chosenNumber = 8;
      break;
      case '9':
      var chosenNumber = 9;
      break;
      case '10':
      var chosenNumber = 10;
      break;
      }
      var x = totalNumberOfFiles / chosenNumber;
      var totalCDs = Math.floor(x);
      if ((totalNumberOfFiles % chosenNumber) !== 0)
      {
        totalCDs = Math.floor(x) + 1;
        totalNumberOfFiles = totalNumberOfFiles + 10;
      }
      var m3uName;
      function createCD(currentCDNumber)
      {
        var getCdNumber = numberCDS(currentCDNumber);
          if (currentCDNumber <= totalCDs)
          {
            m3uName = audiobookFolderName + "_CD" + getCdNumber + ".m3u";
            return m3uName;
          }
      }
        fso = new ActiveXObject("Scripting.FileSystemObject");
        var i = 0;
        var k = 1;
        do {
            for(incrementbyChosen = 0; incrementbyChosen <= totalNumberOfFiles; incrementbyChosen += chosenNumber)
            {
              createCD(k);
              if (k * chosenNumber == incrementbyChosen)
              {
                if (typeof m3uName !== "undefined")
                {
                f1 = fso.CreateTextFile(audiobookFolderPath + "\\" + m3uName, ForWriting);
                }
                for (i; i < objFiles.length && i < incrementbyChosen; i++)
                {
                    if (objFiles[i] != null)
                    {
                         f1.Write((objFiles[i].name) + '\r');
                    }
                }
              }
            }
            k++;
        } while (k <= totalCDs);
      {
      delete objFiles;
      }
   delete objEnum;
   }
}