function show_menu(obj_s,obj){
var s_id = document.getElementById(obj_s);
var sc_id = document.getElementById(obj);
s_id.style.display = "";
sc_id.className = "ahv";
}
function hide_menu(obj_h,obj){
var h_id = document.getElementById(obj_h);
var hc_id = document.getElementById(obj);
h_id.style.display = "none";
hc_id.className = "alk";
}