function scanSubFolders(tFolder)  
{  
   var sFoldersAndFiles = new Array();     
   var sFolders = new Array(); 
    
   sFoldersAndFiles = tFolder.getFiles(); 
    
   for (var j = 0; j < sFoldersAndFiles.length; j++) 
   {     
      if (sFoldersAndFiles[j] instanceof Folder) 
      { 
        sFolders.push(sFoldersAndFiles[j].name); 
      } 
   } 
    
   return sFolders;   
} 
 
var topFolder  = new Folder ('/c/');    
var allFolders = scanSubFolders(topFolder);            
var myString = allFolders.join(",\n"); 
alert("Meine Unterverzeichnisse: " + myString);