function submenu_hidden()
{
    var sub_menu;
    
    for(i=1;i<10;i++) {
        sub_menu = eval("document.all.sub_menu_0" + i);
        if(sub_menu != undefined) {
            sub_menu.style.display = "none";
        }
    }
}

function menu_back_hidden()
{
    var menu_back;
    
    for(i=1;i<10;i++) {
        menu_back = eval("document.all.menu_tbl_0" + i);
        if(menu_back != undefined) {
            menu_back.background = "";
        }
    }
}

function menu_over(num)
{
    var menu_back = eval("document.all.menu_tbl_0" + num);
    menu_back_hidden();
    menu_back.background="http://images.payopen.co.kr/2004/top_bg_01.gif";
    
    var sub_menu = eval("document.all.sub_menu_0"+num);
    submenu_hidden();
    sub_menu.style.display  = "block";
}