Javascript module using jQueryUI.autocomplete and

Let's suppose I want to use jQueryUi.autocomplete for making a module which take the source from a backboneCollection.

I implement the following code (1) for the autocomplete module and
the following for the Backbone.view (2).

Actually, I don't like it because the fetching of the collection is performed also when the user does not type any letter.

How should I perform the fetching collection or the source function only when the user starts to type something in the input box?

P.S.:
I have already posted a similar question jQuery Autocomplete Plugin using Backbone JS , but since the needs of aoutocomplete module could be shared between different view I decided to move the fetch of the collection in autocomplete module.

(1)

/*global define */
define([
    'users',
    'jquery',
    'jqueryUi'
], function (UserCollection, $) {
    "use strict";
    var autoComplete = function(element) {

        var userCollection,
            data;

        userCollection = new UserCollection(); 
        userCollection.fetch();

        data =  userCollection.toJSON();

        element.autocomplete({
            minLength: 3,
            source: function(request, response) {
                var matcher = new RegExp($.ui.autocomplete.escapeRegex(request.term), "i");
                response($.grep(data, function(value) {
                    return matcher.test(value.name);
                }));
            },
            create: function() {
                element.val(data.name);
            },
            focus: function(event, ui) {
                element.val(ui.item.name);
                return false;
            },
            select: function(event, ui) {
                element.val(ui.item.name);
                return false;
            }
        }).data('autocomplete')._renderItem = function(ul, item) {
            return $('<li></li>')
                .data('item.autocomplete', item)
                .append('<a><img src="' + item.avatar + '" />' + item.name + '<br></a>')
                .appendTo(ul);
        };
    };

    return autoComplete;
});

(2)

// View1 (view using the module autocomplete)
define([
    'autoCompleteModule'
], function (autoCompleteModule) {
    var MyView = Backbone.View.extend({

        events: {
            'focus #names': 'getAutocomplete'
        },
        getAutocomplete: function (e) {
            autoCompleteModule($('#names'));
        }
    });
});

//Pseudo code from jQuery Autocomplete Plugin using Backbone JS

var MyView = Backbone.View.extend({
initialize: function () {
    this.myCollection = new MyCollection();

},
events: {
    'focus #names': 'getAutocomplete',
    'keydown #names':'invokefetch'
},
invokefetch : function(){
   this.myCollection.fetch(); 
   $("#names").unbind( "keydown", invokefetch);
},    
getAutocomplete: function () {
    $("#names").autocomplete({
        source: JSON.stringify(this.myCollection)
    });
}

});

EDIT-20120711--------- how about this:

//Pseudo code ...

// View1 (view using the module autocomplete)
define([
    'autoCompleteModule'
], function (autoCompleteModule) {
    var MyView = Backbone.View.extend({

        events: {
            'keydown #names': 'getAutocomplete'
        },
        getAutocomplete: function (e) {
            var el = $('#names');
            if(!el.data){
                autoCompleteModule(el);
            }
        }
    });
});