Question

I’d like to make this better/simpler, so further functions can be added later?

$(function() {
$('#boroughs').change(function() {
$('.boroughs').hide();
$('.fitness').hide();
$('#' + $(this).val()).show();
});
});
$(function() {
$('#b1').change(function() {
$('.fitness').hide();
$('#' + $(this).val()).show();
});
});
$(function() {
$('#b2').change(function() {
$('.fitness').hide();
$('#' + $(this).val()).show();
});
});

Answer 1

        $(function () {
        $('#b1,#boroughs,#b2').change(function () {
            if ($(this).attr('id') == 'boroughs')
                $('.boroughs').hide();
            $('.fitness').hide();
            $('#' + $(this).val()).show();
        });
    });