function changePage(step, count, select) {
    for(i = 1; i <= count; i++) {
        if($('page' + i).style.display == "block") {
            $('page' + i).style.display = "none";
            if(select == 0) {
                $('btnSelect_produkteSeiten').selectedIndex = 0;
                if(step == 1) {
                    if(i == count) {
                        $('page1').style.display = "block";
                        $('act_page').innerHTML  = 1;
                    } else {
                        $('page' + (i + 1)).style.display = "block";
                        $('act_page').innerHTML           = (i + 1);
                        $('act_page_bottom').innerHTML    = (i + 1);
                    }
                    break;
                } else {
                    if(i == 1) {
                        $('page' + count).style.display = "block";
                        $('act_page').innerHTML         = count;
                    } else {
                        $('page' + (i - 1)).style.display = "block";
                        $('act_page').innerHTML           = (i - 1);
                        $('act_page_bottom').innerHTML    = (i - 1);
                    }
                    break;
                }
            } else {
                $('page' + select).style.display = "block";
                $('act_page').innerHTML          = select;
                $('act_page_bottom').innerHTML   = select;
            }
        }
    }
}