function switchSearchMenu(curr_id, total_num) {    
 for(var i=0; i<total_num; i++)     {                     
     var el = document.getElementById('search_menu_sub_'+i);  
     if(!el) return;        
     if(i == curr_id) {   
          el.style.display = "block";                                                                
      } else{            
          el.style.display = "none";
     } 
  } 
}