text: (function () {
    var lastTime = 0
    var vendors = ['webkit', 'moz']
    for (var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
      window.requestAnimationFrame = window[vendors[x] + 'RequestAnimationFrame']
      window.cancelAnimationFrame = window[vendors[x] + 'CancelAnimationFrame'] || window[vendors[x] + 'CancelRequestAnimationFrame']
    }
    if (!window.requestAnimationFrame) {
      window.requestAnimationFrame = function (callback, element) {
        var currTime = new Date().getTime()
        var timeToCall = Math.max(0, 16 - (currTime - lastTime))
        var id = window.setTimeout(function () { callback(currTime + timeToCall) }, timeToCall)
        lastTime = currTime + timeToCall
        return id
      }
    }
  
    if (!window.cancelAnimationFrame) {
      window.cancelAnimationFrame = function (id) {
        clearTimeout(id)
      }
    }
  }())
  