[jQuery] Re: UI slider execute function on change or slide

I've changed my markup to:

    <div id="ariaslider">
        <form action="#">
                <!-- Slider -->
                <fieldset>
                        <select name="sizer" id="speed">
                                <option value="10">10</option>
                                <option value="20">20</option>
                                <option value="21" 
selected="selected">21</option>
                                <option value="30">30</option>
                                <option value="40">40</option>
                        </select>
                </fieldset>
        </form>
        </div>

and code to:

        <script type="text/javascript">
                $(function(){
                        //demo 1
                        var abc = $('select#sizer').selectToUISlider().next();
                        var setfontsize = $('#sizer :selected').text();

                        $('#ariaslider').slider({change: function(event, ui) {
                                $('.cica').css("font-size", setfontsize + 
"px");}
});
                        $('#ariaslider').bind('slidechange', function(event, 
ui) {
                                $('.cica').css("font-size", setfontsize + "px");
});


});
</script>

I am not quite sure of what it does, I am trying to get more info on
how bind works... It now change the first size and then it blocks.
Thank you for your help.