Is it possible to modify this script to include subfolders?

Question

I have tried to do this with no luck. This script works great, but how to I make it apply to all sub-folders? Thanks for any suggestions.
#target bridge  
if( BridgeTalk.appName == "bridge" ) { 
descToTitle = MenuElement.create("command", "Keys to Title", "at the end of Tools");
descToTitle.onSelect = function () {
if (ExternalObject.AdobeXMPScript == undefined) ExternalObject.AdobeXMPScript = new ExternalObject("lib:AdobeXMPScript");
var thumb = app.document.selections;
    for(var s in thumb){
if(thumb[s].hasMetadata){
        var selectedFile = thumb[s].spec;
  var myXmpFile = new XMPFile( selectedFile.fsName, XMPConst.UNKNOWN, XMPConst.OPEN_FOR_UPDATE);
  var myXmp = myXmpFile.getXMP();
         var Description =  getArrayItems(XMPConst.NS_DC, "keywords");
        myXmp.deleteProperty(XMPConst.NS_DC, "title");
        myXmp.appendArrayItem(XMPConst.NS_DC, "title", Description, 0, XMPConst.ALIAS_TO_ALT_TEXT);
        myXmp.setQualifier(XMPConst.NS_DC, "title[1]", "http://www.w3.org/XML/1998/namespace", "lang", "x-default");
function getArrayItems(ns, prop){
var arrItem=[];
try{
var items = myXmp.countArrayItems(ns, prop);
for(var i = 1;i <= items;i++){
arrItem.push(myXmp.getArrayItem(ns, prop, i));
return arrItem;
}catch(e){alert(e +" Line: "+ e.line);}
        if (myXmpFile.canPutXMP(myXmp)) {
        myXmpFile.putXMP(myXmp);
        myXmpFile.closeFile(XMPConst.CLOSE_UPDATE_SAFELY);
         } else {
  xmpFile.closeFile();

Answer 1

I have done that, but for some reason that feature is not working in my copy of Bridge.
Not to mention, I need to do this on thousands of images. That is why the subfolder feature would be helpful.
However, I also thought about creating a collection with all of the images in it.