2 lines of JQuery not working in IE but work fine in FF
===

I have a site that has 4 drop downs. I have added JQuery code so that if a user changes one of the drop down selections the remaining drop downs that are below the changed one resets to default. Everything works if FF but not IE. Any help with be great!

The last 2 lines of code is the only part not working. 



jQuery(".chainedSelectsShowNextOrGoToUrlLabel").change(function() {
        var urllabel, urllabelall, $this, $sel, prevvalue, allVal, next, previousValue;

        $this = jQuery(this);
        currentSelectObjName = jQuery(this).attr('name');
        $sel = $this.children(':selected');
        currentSelectedValue = $sel.val();
        urllabel = $sel.attr('urllabel');
        urllabelall = $sel.attr('urllabelall');

        //go to url if it has a urllabel attr
        if (typeof urllabel !== 'undefined') {
            window.location.href = urllabel;
            return;
        }

        //if its a urllabelall go to previous values in form and see if they match
        //if it does go to the url !
        if (typeof urllabelall !== 'undefined') {

            allVal = '';
            jQuery(".chainedSelectsShowNextOrGoToUrlLabel").each(function() {
                allVal += $(this).val();
            });
            prevvalue = $sel.attr('prevvalue') + $this.val();

            if (prevvalue === allVal) {
                window.location.href = urllabelall;
                return;
            }
        }

        if ($this.val() !== "") {
            $this.parents('tr').next().removeClass('hidden').show();
        }

        parentTr = jQuery(this).parent().parent();
        jQuery(parentTr).nextAll().find('option').removeAttr('selected');


    });
