Как да добавя в този код месец и година някой знае ли ? 
var oneMinute = 60 //minute unit in seconds
var oneHour = 60*60 //hour unit in seconds
var oneDay = 60*60*24 //day unit in seconds
var dayfield = Math.floor(timediff/oneDay)
var hourfield = Math.floor((timediff - dayfield * oneDay) / oneHour)
var minutefield = Math.floor((timediff - dayfield * oneDay - hourfield * oneHour) / oneMinute)
var secondfield = Math.floor((timediff - dayfield * oneDay - hourfield * oneHour - minutefield * oneMinute))