var menu_height= 32;
var delay= 20;
var step = 10;
var temp_height;

function inc_menu (el,el_child,n) {
   if (temp_height < menu_height * n - step) {
      temp_height = temp_height + step;
      el.style.height = temp_height + 'px';
      setTimeout( "inc_menu(el,el_child,"+n+")" ,delay);
   } else {
      temp_height = menu_height * n;
      el.style.height = temp_height +'px';
      el_child.style.display='block';
   }
}

function dec_menu (el,el_child,n) {
   if (temp_height > step) {
      temp_height = temp_height - step;
      el.style.height = temp_height + 'px';
      setTimeout("dec_menu(el,el_child,"+n+")",delay);
   } else {
      el.style.height = temp_height + 'px';
      el.style.display = '';
   }
}

function toggle_menu(m,n) {
   step=n*2;
   a=parseInt(n)
   el = document.getElementById(m);
   el_child = document.getElementById(m+'-content');
   if (el.style.display != 'block') {
      temp_height = 0;
      el.style.display = 'block';
      inc_menu(el,el_child,a);
      }
   else {
      temp_height = menu_height * a;
      el_child.style.display='';
      dec_menu(el,el_child,a);
   }
}