// JavaScript Document
 
var y = 0;
var step = 10;
var down = true;
var minstep=step;
var running=false;
var t;
 
 
function smooth_on_off(p_id, hmax){
  running=true;
  obj=document.getElementById(p_id);
  
  if(y>hmax&&down){
  				step=-step;
                down=false;
                running=false;
                clearInterval(t);
                return false;
				}
  if(y<minstep&&!down){
  				step=-step;
                down=true;
                running=false;
                y=1;
                clearInterval(t);
                return false;
				}
 
  y = y+step;
   
  obj.style.height = y + 'px';
}
 
function deroule(p_id,hmax){
if (running) {return false;}
t=setInterval(function(){smooth_on_off(p_id,hmax)},1)
 
}