<div>
  <div class="box a"></div>
  <div class="box b"></div>
  <div class="box c"></div>
</div>
<button class="start">Start Animation</button>

body {
  margin: 20px;
  font-family: 'Lato';
  font-weight: 300;
  text-align: center;
}

.box {
  width: 100px;
  height: 100px;
  display: inline-block;
  border: 2px solid black;
  margin: 10px;
  opacity: 0.1;
}

.a {
  background: orange;
}

.b {
  background: red;
}

.c {
  background: yellow;
}

button {
  background: wheat;
  border: 1px solid black;
  font-family: 'Lato';
  border-radius: 5px;
  padding: 8px;
  margin: 20px 0;
  outline: none;
  cursor: pointer;
}

var theBoxes = document.querySelectorAll(".box");
var startButton = document.querySelector(".start");

var animateOpacity = KUTE.allFromTo(
  theBoxes,
  { opacity: 1 },
  { opacity: 0.1 },
  { offset: 700 }
);

startButton.addEventListener(
  "click",
  function() {
    animateOpacity.start();
  },
  false
);