I am using Symfony 2 to develop an application and I have imported the jQuery UI in this way:

            <link href="{{ asset('bundles/javascript/jquery-ui-1.11.1.custom/jquery-ui.css') }}" rel="stylesheet" media="screen">

            <script type="text/javascript" src="{{ asset('bundles/javascript/jquery-1.11.1.min.js') }}"></script>

            <script type="text/javascript" src="{{ asset('bundles/javascript/jquery-ui-1.11.1.custom/external/jquery/jquery.js') }}"></script>

            <script type="text/javascript" src="{{ asset('bundles/javascript/jquery-ui-1.11.1.custom/jquery-ui.js') }}"></script>

When I load the page in the browser (Mozilla Firefox and Google Chrome) those files seems to be correctly loaded, the problem in that firebug throws an error and the jQuery functions doesn't exists, firebug says:

In Mozilla Firefox: TypeError: $(...).datepicker is not a function

In Google Chrome: Uncaught TypeError: undefined is not a function 

I have investigated on the internet how can I fix this problem, but all sollutions I found don't give me the answer, any ideas?

Thanks!