Just some funzies with CSS3 animations. If you are worried about super deep browser support, use a GIF.

<div class="loader">
    <span></span>
    <span></span>
    <span></span>
</div>

.loader {
    text-align: center;    
}
.loader span {
    display: inline-block;
 

    vertical-align: middle;
    width: 10px;
    height: 10px;
    margin: 50px auto;
    background: black;
    border-radius: 50px;
    -webkit-animation: loader 0.9s infinite alternate;
    -moz-animation: loader 0.9s infinite alternate;
}
.loader span:nth-of-type(2) {
    -webkit-animation-delay: 0.3s;
 

    -moz-animation-delay: 0.3s;
}
.loader span:nth-of-type(3) {
    -webkit-animation-delay: 0.6s;
    -moz-animation-delay: 0.6s;
}
@-webkit-keyframes loader {
  0% {
    width: 10px;
    height: 10px;
    opacity: 0.9;
    -webkit-transform: translateY(0);
  }
  100% {
    width: 24px;
    height: 24px;
    opacity
 
: 0.1;
    -webkit-transform: translateY(-21px);
  }
}
@-moz-keyframes loader {
  0% {
    width: 10px;
    height: 10px;
    opacity: 0.9;
    -moz-transform: translateY(0);
  }
  100% {
    width: 24px;
    height: 24px;
    opacity: 0.1;
    -moz-transform: translateY(-21px);
  }
}

注：作者資訊已在轉載文章中註明。

原文連結：

https://css-tricks.com/snippets/css/bouncy-animated-loading-animation/