very simple approach to using jQuery UI's autocomplete. This is very *rough* and is just meant to give you an idea of how you might use th autocomplete widget with a Backbone View (use only as a start :)).

gistfile1.txt

var AutocompleteView = Backbone.View.extend({
  
  initialize: function() {
        this.availableTags = [
            "ActionScript",
            "AppleScript",
            "Asp",
            "BASIC",
            "C",
            "C++",
            "Clojure",
            "COBOL",
            "ColdFusion",
            "Erlang",
            "Fortran",
            "Groovy",
            "Haskell",
            "Java",
            "JavaScript",
            "Lisp",
            "Perl",
            "PHP",
            "Python",
            "Ruby",
            "Scala",
            "Scheme"
        ];
  }

  render: function() {
    this.$el.html('<input id="tags">');
    this.$el.find('#tags')..autocomplete({
      source: this.availableTags
    });
});

var view = new AutocompleteView();
$('body').append(view.render().el);