var speed = 1;
  var position_ini = 0;
  var alt = 1;
  var pos_ini1 = 0, pos_ini2 = -1;
  var dir=1;
  var stp;
  
  function defil()
  {
  	if (stp==1) return;
    /*if (document.all){*/
		 temp = document.getElementById('left').scrollTop;
    /*}
    else{
		 temp =  document.getElementById('left').pageYOffset;
    }*/
    if (alt == 0){
		 alt = 1;
    }
    else{
		alt = 0;
    }
    if (alt == 0){
	   pos_ini1 = temp;
    }
    else{
	  pos_ini2 = temp;
    }
    if (pos_ini1 != pos_ini2)
		{
		if (dir==1)
			{
			/*if (document.all){*/
				  position_ini = document.getElementById('left').scrollTop + speed;
				/*}
				else{
				  position_ini = document.getElementById('left').pageYOffset + speed;
				}*/
			}
		else
			{
			/*if (document.all){*/
				  position_ini = document.getElementById('left').scrollTop - speed;
				/*}
				else{
				  position_ini = document.getElementById('left').pageYOffset - speed;
				}*/
			}
			document.getElementById('left').scrollTop = position_ini;
		}
    else
		{	
		dir=1-dir;
		pos_ini2-=1;
		}
    return true;
  }

  function initdefil()
  {
    setInterval("defil()", 50);
    return true;
  }
//window.onload = init;