old_contents: 'use strict';
  
  var initClasses   = ['mui-enter', 'mui-leave'];
  var activeClasses = ['mui-enter-active', 'mui-leave-active'];
  
  // Find the right "transitionend" event for this browser
  var endEvent = (function() {
    var transitions = {
      'transition': 'transitionend',
      'WebkitTransition': 'webkitTransitionEnd',
      'MozTransition': 'transitionend',
      'OTransition': 'otransitionend'
    }
    var elem = window.document.createElement('div');
  
    for (var t in transitions) {
      if (typeof elem.style[t] !== 'undefined') {
        return transitions[t];
      }
    }
  })();
  
  function animate(isIn, element, animation, cb) {
    element = $(element).eq(0);
  
    if (!element.length) return;
  
    var initClass = isIn ? initClasses[0] : initClasses[1];
    var activeClass = isIn ? activeClasses[0] : activeClasses[1];
  
    // Set up the animation
    reset();
    element.addClass(animation);
    element.css('transition', 'none');
    requestAnimationFrame(function() {
      element.addClass(initClass);
      if (isIn) element.show();
    });
  
    // Start the animation
    requestAnimationFrame(function() {
      element[0].offsetWidth;
      element.css('transition', '');
      element.addClass(activeClass);
    });
  
    // Clean up the animation when it finishes
    element.one('transitionend', finish);
  
    // Hides the element (for out animations), resets the element, and runs a callback
    function finish() {
      if (!isIn) element.hide();
      reset();
      if (cb) cb.apply(element);
    }
  
    // Resets transitions and removes motion-specific classes
    function reset() {
      element[0].style.transitionDuration = 0;
      element.removeClass(initClass + ' ' + activeClass + ' ' + animation);
    }
  }
  
  var MotionUI = {
    animateIn: function(element, animation, cb) {
      animate(true, element, animation, cb);
    },
  
    animateOut: function(element, animation, cb) {
      animate(false, element, animation, cb);
    }
  }
  
new_contents: 'use strict';
  
  // Polyfill for requestAnimationFrame
  (function() {
    if (!Date.now)
      Date.now = function() { return new Date().getTime(); };
  
    var vendors = ['webkit', 'moz'];
    for (var i = 0; i < vendors.length && !window.requestAnimationFrame; ++i) {
        var vp = vendors[i];
        window.requestAnimationFrame = window[vp+'RequestAnimationFrame'];
        window.cancelAnimationFrame = (window[vp+'CancelAnimationFrame']
                                   || window[vp+'CancelRequestAnimationFrame']);
    }
    if (/iP(ad|hone|od).*OS 6/.test(window.navigator.userAgent)
      || !window.requestAnimationFrame || !window.cancelAnimationFrame) {
      var lastTime = 0;
      window.requestAnimationFrame = function(callback) {
          var now = Date.now();
          var nextTime = Math.max(lastTime + 16, now);
          return setTimeout(function() { callback(lastTime = nextTime); },
                            nextTime - now);
      };
      window.cancelAnimationFrame = clearTimeout;
    }
  })();
  
  var initClasses   = ['mui-enter', 'mui-leave'];
  var activeClasses = ['mui-enter-active', 'mui-leave-active'];
  
  // Find the right "transitionend" event for this browser
  var endEvent = (function() {
    var transitions = {
      'transition': 'transitionend',
      'WebkitTransition': 'webkitTransitionEnd',
      'MozTransition': 'transitionend',
      'OTransition': 'otransitionend'
    }
    var elem = window.document.createElement('div');
  
    for (var t in transitions) {
      if (typeof elem.style[t] !== 'undefined') {
        return transitions[t];
      }
    }
  
    return null;
  })();
  
  function animate(isIn, element, animation, cb) {
    element = $(element).eq(0);
  
    if (!element.length) return;
  
    if (endEvent === null) {
      isIn ? element.show() : element.hide();
      cb();
      return;
    }
  
    var initClass = isIn ? initClasses[0] : initClasses[1];
    var activeClass = isIn ? activeClasses[0] : activeClasses[1];
  
    // Set up the animation
    reset();
    element.addClass(animation);
    element.css('transition', 'none');
    requestAnimationFrame(function() {
      element.addClass(initClass);
      if (isIn) element.show();
    });
  
    // Start the animation
    requestAnimationFrame(function() {
      element[0].offsetWidth;
      element.css('transition', '');
      element.addClass(activeClass);
    });
  
    // Clean up the animation when it finishes
    element.one('transitionend', finish);
  
    // Hides the element (for out animations), resets the element, and runs a callback
    function finish() {
      if (!isIn) element.hide();
      reset();
      if (cb) cb.apply(element);
    }
  
    // Resets transitions and removes motion-specific classes
    function reset() {
      element[0].style.transitionDuration = 0;
      element.removeClass(initClass + ' ' + activeClass + ' ' + animation);
    }
  }
  
  var MotionUI = {
    animateIn: function(element, animation, cb) {
      animate(true, element, animation, cb);
    },
  
    animateOut: function(element, animation, cb) {
      animate(false, element, animation, cb);
    }
  }
  
subject: Add requestAnimationFrame polyfill and add IE9 compatibility