var hTimer = 0;
var norm = 0, offset = 0, i = 0;
if ( document.getElementById("history") != null )
	hTimer = window.setInterval("shake()", 15000);
	
function shake () {
  offset = (offset==0) ? 3 : 0;
  document.getElementById("history").style.paddingBottom=(norm+offset)+"px";
  
  if (i++ > 10)
    window.clearInterval(hTimer);
	
}