var obj = null;
var aLis = null;
var oBar = null;
var iTime = null;
var iSpeed = 0;
var iAcc = 3;
var onOff = 0;
var iPrev = 0;
var iNext = 0;
function goTime()
{
 for(var i = 0; i < aLis.length; i+=1)
 {
  if(aLis[i] === this)
  {
   var iTarget = (aLis[0].offsetHeight + 5) * i;
 
   iNext = i;
   
   onOff = iNext - iPrev;
   
   if(iTime)
   {
    clearInterval(iTime);
   }
   
   if(onOff>=0)
   {
    iTime = setInterval("elasticity("+ iTarget +")",35);
   }
   else
   {
    iTime = setInterval("postpone("+ iTarget +")",35);
   }
   
   iPrev = iNext;
  }
 
  aLis[i].className="";
  this.className="active";
 }
}
 
function elasticity(target)
{
 var top = oBar.offsetTop;
 iSpeed+=iAcc;
 top += iSpeed;
 if(top >= target)
 {
  iSpeed*=1;
  
  if(Math.abs(iSpeed)<=iAcc)
  {
   clearInterval(iTime);
   iTime=null;
  }
  
  top=target;
 }
 oBar.style.top = top + "px";
}
 
function postpone(target)
{
 if(oBar.offsetTop===target)
 {
  clearInterval(iTime);
  iTime=null;
 }
 else
 {
  iSpeed = (target - oBar.offsetTop)/4;
  oBar.style.top = oBar.offsetTop + iSpeed + "px";
 }
}
 
window.onload = function(){
 obj = document.getElementById("nav");
 aLis = obj.getElementsByTagName("li");
 oBar = document.getElementById("bar");
 for(var i = 0; i < aLis.length; i+=1)
 {
  if(aLis[i].id!="bar")
  {
   aLis[i].onmouseover = goTime;   
  }
 }
}