[jQuery] Multiple classes selector causing trouble, but why ??

[elpatator]

Hi all,

i'm struggling with a small yet in,teresting problem. In order to
allow users to filter content, i've created a small checkbox list. To
each checkbox is attached an ID , and too some divs on the page are
attached these id's too (in the class attr that is); one div can be
attached to multiple id's, and so have multiple classes.
In order to show or hide my div's I wrote :

                function couponsVisibles(){
                        $('.checkInteret').each(function(){
                                var coche = $(this).attr("checked");
                                if (coche) {
                                        var idCoupons = $(this).attr("id");
                                        $(".zoneCoupon , div[class='" 
+idCoupons+ "']").each(function(){
                                                        $(this).fadeIn();
                                        });
                                }
                        });
                }

                $(".checkInteret").click(function(){
                                var coche = $(this).attr("checked");
                                if (!coche) {
                                        var idCoupons = $(this).attr("id");
                                        $(".zoneCoupon , div[class='" 
+idCoupons+ "']").each(function(){

                                                        $(this).fadeOut();
                                        });
                                }
                        couponsVisibles();
                });

It looks like my selector "$(".zoneCoupon , div[class='" +idCoupons+
"']")" doesn't work, but I can't figgure out why.
Oh, and, btw, I've started using the [attribute*=value]  selector, but
this selector doesn't seem to make a difference beetween class='8 10'
and class='8 1'...

Help really appreciated, thx !!