<div id="container">
  <div id="inner"></div>
</div>

body {
  /* Full screen width and height */
  width: 100%;
  min-height: 100vh;

  /* Centers the container in the middle of the screen */
  display: flex;
  justify-content: center;
  align-items: center;

  margin: 0;
  background-color: rgb(220, 220, 220);
}

#container {
  perspective: 25px;
}

#inner {
  width: 20em;
  height: 18em;
  background-color: white;
  box-shadow: 2px 2px 50px rgba(0, 0, 0, 0.2);
  transition: transform 0.5s;
  -webkit-transition: transform 0.5s;
  -moz-transition: transform 0.5s;
  -o-transition: transform 0.5s;
}

(function() {
  // Init
  var container = document.getElementById("container"),
    inner = document.getElementById("inner");

  // Mouse
  var mouse = {
    _x: 0,
    _y: 0,
    x: 0,
    y: 0,
    updatePosition: function(event) {
      var e = event || window.event;
      this.x = e.clientX - this._x;
      this.y = (e.clientY - this._y) * -1;
    },
    setOrigin: function(e) {
      this._x = e.offsetLeft + Math.floor(e.offsetWidth / 2);
      this._y = e.offsetTop + Math.floor(e.offsetHeight / 2);
    },
    show: function() {
      return "(" + this.x + ", " + this.y + ")";
    }
  };

  // Track the mouse position relative to the center of the container.
  mouse.setOrigin(container);

  //-----------------------------------------

  var counter = 0;
  var updateRate = 10;
  var isTimeToUpdate = function() {
    return counter++ % updateRate === 0;
  };

  //-----------------------------------------

  var onMouseEnterHandler = function(event) {
    update(event);
  };

  var onMouseLeaveHandler = function() {
    inner.style = "";
  };

  var onMouseMoveHandler = function(event) {
    if (isTimeToUpdate()) {
      update(event);
    }
  };

  //-----------------------------------------

  var update = function(event) {
    mouse.updatePosition(event);
    updateTransformStyle(
      (mouse.y / inner.offsetHeight / 2).toFixed(2),
      (mouse.x / inner.offsetWidth / 2).toFixed(2)
    );
  };

  var updateTransformStyle = function(x, y) {
    var style = "rotateX(" + x + "deg) rotateY(" + y + "deg)";
    inner.style.transform = style;
    inner.style.webkitTransform = style;
    inner.style.mozTransform = style;
    inner.style.msTransform = style;
    inner.style.oTransform = style;
  };

  //-----------------------------------------

  container.onmouseenter = onMouseEnterHandler;
  container.onmouseleave = onMouseLeaveHandler;
  container.onmousemove = onMouseMoveHandler;
})();