function page(page) {
        var t = document.getElementById('data_table');
        var page_num = document.getElementById('all_page').value;
 
        if(page_num == 1)         
          return;   

        var res;
        if (page=="previous")
                res=Table.pagePrevious(t);
        else if (page=="next")
                res=Table.pageNext(t);
        
        var p = document.getElementById("previous");
        var n = document.getElementById("next"); 
        
        if(res.page == page_num-1)
            n.className = "gray_w";
        else
            n.className = "";

        if(res.page == 0)
            p.className = "gray_w";
        else
            p.className = "";           
}