Bouncing box with CSS3

bounce.css

/*
  Example https://jsfiddle.net/spxkmwau/
*/
@-webkit-keyframes bounce {
  0%,
  20%,
  50%,
  80%,
  100% {
    -webkit-transform: translateY(0);
  }
  40% {
    -webkit-transform: translateY(-2px);
  }
  60% {
    -webkit-transform: translateY(-2px);
  }
}
@keyframes bounce {
  0%,
  20%,
  50%,
  80%,
  100% {
    transform: translateY(0);
  }
  40% {
    transform: translateY(-2px);
  }
  60% {
    transform: translateY(-2px);
  }
}
.bounce {
  -webkit-animation-name: bounce;
  animation-name: bounce;
  -webkit-animation-duration: 0.5s;
  animation-duration: -0.5s;
  -webkit-animation-fill-mode: both;
  animation-fill-mode: both;
  animation-iteration-count: infinite;
  -webkit-animation-iteration-count: infinite;
}

.box {
  width: 150px;
  height: 30px;
  border: 1px solid black;
  text-align: center;
}

bounce.html

<div class="box bounce">Click me!</div>