$("#id_select_{{field_id}}").autocomplete({
    source: {{source}},
    select: function( event, ui ) {
            if(ui.item){
                $('#id_{{field_id}}').val(ui.item.id);
            } else {
                $('#id_{{field_id}}').val(null);
            }
        },
    minLength: 2{% if options %},
    {{options}}
    {% endif %}
});

$('#id_select_{{field_id}}').live('click', function(){
    $('#id_{{field_id}}').val(null);
    $('#id_select_{{field_id}}').val(null);
});