Spotify multiple input jquery-ui autocomplete

gistfile1.js

function split( val ) {
  return val.split( /;\s*/ );
}

function extractLast( term ) {
  return split( term ).pop();
}

$("#spotify_song_search").bind( "keydown", function( event ) {
    if ( event.keyCode === $.ui.keyCode.TAB && $( this ).data( "ui-autocomplete" ).menu.active ) {
      event.preventDefault();
    }
  }).autocomplete({
	source: function(request, response) {
			$.get("http://ws.spotify.com/search/1/track.json", {
					q: extractLast( request.term  )
			}, function(data) {
					response($.map(data.tracks, function(item) {
							return {label: item.name + " by " + item.artists[0].name, track: item};
					}));
			});
	},
	focus: function() {
      // prevent value inserted on focus
    return false;
  },
  select: function( event, ui ) {
    var terms = split( this.value );
    // remove the current input
    terms.pop();
    // add the selected item
    terms.push( ui.item.value );
    // add placeholder to get the comma-and-space at the end
    terms.push( "" );
    this.value = terms.join( "; " );
    return false;
  },
	minLength: 3,

});