function validate_registration ()
    {
        var errors = "The following fields are required:\n";
        var post = true;

        if ( $('input#title').val() == "" )
        {
            errors += "Title\n";
            post = false;
        }

        if ( $('textarea#intro').val() == "" )
        {
            errors += "Introduction\n";
            post = false;
        }

        if ( $('textarea#detail1').val() == "" )
        {
            errors += "Detail\n";
            post = false;
        }

        if ( post == false ) alert ( errors );
        return post;
    }

    function selection_changed ()
        {
            var age_count = $("#age_group .short_list tr.data_row").size ();

            if ( age_count > 0 )
            {
                $(".buttons_table .button_wrapper.add_button").removeClass ( "disabled" );
                $(".buttons_table .button_wrapper.reset_button").removeClass ( "disabled" );
            } else {
                $(".buttons_table .button_wrapper.add_button").addClass ( "disabled" );
                $(".buttons_table .button_wrapper.reset_button").addClass ( "disabled" );
            }
        }

    $(document).ready ( function () {

        $('input#filter_submit').click( function () {
                if ( validate_registration() == false )
                {
                    return false;
                }
                else
                {
                    $('input#filter_submit').submit();
                }
            });

        $.multiselect ( "#age_group", "/main/age_groups", {
                onchange: function () {
                    selection_changed ();
                }
            } );
        });