function cahngeTab(id) {
        for(var i=1;i<=3;i++) {
            tmp_id = 'ps'+i;
            if(tmp_id != id){
                document.getElementById(tmp_id).className = "products_unselected";
                document.getElementById('pd'+i).style.display = "none";
            }
        }
        document.getElementById('ps'+id).className = "products_selected";
        document.getElementById('pd'+id).style.display = "block";
    }
    function showHideNews(id) {
        document.getElementById('news_'+oldNewsId).style.display = 'none';
        document.getElementById('news_'+id).style.display = 'block';
        oldNewsId = id;
    }