jQuery - Count elements with a certain class inside a parent element

I got this HTML structure:

<form>
    <input class="myTrigger" type="radio" value="1"/>
    <开发者_如何学Go;input class="myTrigger" type="radio" value="2"/>
    <fieldset>
        <ul class="class1">
            <li></li>
        </ul>
        <ul class="class2">
            <li></li>
        </ul>
    </fieldset>
    <fieldset>
        <ul class="class2">
            <li></li>
        </ul>
        <ul class="class2">
            <li></li>
        </ul>
    </fieldset>
</form>

With jQuery, I need to go through each ul and hide the ones that don't have class myClass (wich is defined by the checked radio .myTrigger) then i need to check for the now empty fieldset's (ie: fieldsets where no ul has class myClass) and hide them entirely.

So far, i was able to hide the desired ul's, but not the fieldsets. This is what i got:

function myFunction() {

        var myClass = "class"+($("radio:checked").attr("value"));
        var productGroup = $("form ul");

        $("form fieldset").each(function(index){

            groupCheck = 0;

            $.each(productGroup, function(index, obj){
                if($(obj).hasClass(myClass))
                    {
                        groupCheck += 1;
                        $(obj).show();
                    }
                else
                    {
                        $(obj).hide();
                    };
            })

            if (groupCheck == 0)
                {
                    $(this).hide();
                }
            else {
                    $(this).show();
                };

        });

    };
myFunction();
$(".myTrigger").change(myFunction);

Also i got other scripts on the same page toggling the same ul's ex: (legend).click(function(){$(this).siblings("ul").toggle();}); so can't hide the fieldsets based on the ul's beeing hidden already. instead I need to look for the classes ("myClass") beeing present or not.

(ie: while the small script toogles the ul's just for user convinience "myFunction" needs to filter the ul's and fieldsets to be shown based on "myTrigger" selection.)

No need for loops; just target the things you want to show/hide with appropriate selectors:

var myClass = 'class' + $('radio:checked:first').attr('value');

// Hide all the <ul>s
$('ul.' + myClass).hide();

// First, show all the fieldsets, in case any were hidden earlier
$('fieldset').show(); 

// Now hide the ones that don't have any visible <ul>s inside
$('fieldset:not(:has(ul:visible))').hide();