Loading XML File into Javascript

Question

Hi all, I have an XML file, which can be viewed here,(click "Download File" on the page that the link takes you to, and it will open the XML in your default browser) of data concerning a series of music albums, which I would like to load into javascript into an array called "mymusic" in this form:

mymusic = [
  {
    title:,
    artist:,
    artwork:,
    tracks: [
      {
        tracktitle:,
        trackmp3:
      },
      {
        tracktitle:,
        trackmp3:
      }
    ]
  }
];

etc.; so basically an array of albums, where each album is represented by a record, the fields of which are the album title, album artist, album artwork, and an array of the album's tracks (where each track/index of the array is represented by a record with fields tracktitle and trackmp3.

In order to achieve this I have the following javascript:

function getxml(){
    xmldoc=XML.load('music.xml');
    var xmlalbums=xmldoc.getElementsByTagName('album');
    mymusic=[];
    for(i=0;i<xmlalbums.length;i++){
        xmlalbum=xmlalbums[i];
        mymusic[i]={};
        mymusic[i].title=dataFromTag(xmlalbum,'title');
        mymusic[i].artist=dataFromTag(xmlalbum,'artist');
        mymusic[i].artwork=dataFromTag(xmlalbum, 'artwork');
        tracks=[];
        var xmltracks=xmlalbums[i].getElementsByTagName('track');
        for(var a=0;a<xmltracks.length;a++){
            xmltrack=xmltracks[i];
            tracks[i]={};
            tracks[i].tracktitle=dataFromTag(xmltrack, 'title');
            tracks[i].trackmp3=dataFromTag(xmltrack, 'mp3');
            mymusic[i].tracks=tracks;
        }
    }
}

however, this doesn't load the contents of music.xml in the way I'd like, but I can't see why this is. Any suggestions or help would be appreciated.

Thanks