SOURCE

<div id="loading">
  <div id="loading-center">
    <div id="loading-center-absolute">
      <div class="object" id="object_four"></div>
      <div class="object" id="object_three"></div>
      <div class="object" id="object_two"></div>
      <div class="object" id="object_one"></div>
      <h2>加载中……</h2>
    </div>
  </div>
</div>

#loading {
	background-color: #FFF;
	height: 100%;
	width: 100%;
	position: fixed;
	z-index: 1;
	margin-top: 0px;
	top: 0px;
}
#loading-center {
	width: 100%;
	height: 100%;
	position: relative;
}
#loading-center-absolute {
	position: absolute;
	left: 50%;
	top: 40%;
	height: 200px;
	width: 200px;
	margin-top: -100px;
	margin-left: -100px;
}
h2 {
	color: #17607d;
	font: 12px/30px "Microsoft Yahei";
	margin-top: 200px;
	text-align: center
}
.object {
	-moz-border-radius: 50% 50% 50% 50%;
	-webkit-border-radius: 50% 50% 50% 50%;
	border-radius: 50% 50% 50% 50%;
	position: absolute;
	border-top: 5px solid #17607d;
	border-bottom: 5px solid transparent;
	border-left: 5px solid #17607d;
	border-right: 5px solid transparent;
	-webkit-animation: animate 2s infinite;
	animation: animate 2s infinite;
}
#object_one {
	left: 75px;
	top: 75px;
	width: 50px;
	height: 50px;
}
#object_two {
	left: 65px;
	top: 65px;
	width: 70px;
	height: 70px;
	-webkit-animation-delay: 0.2s;
	animation-delay: 0.2s;
}
#object_three {
	left: 55px;
	top: 55px;
	width: 90px;
	height: 90px;
	-webkit-animation-delay: 0.4s;
	animation-delay: 0.4s;
}
#object_four {
	left: 45px;
	top: 45px;
	width: 110px;
	height: 110px;
	-webkit-animation-delay: 0.6s;
	animation-delay: 0.6s;
}
 @-webkit-keyframes animate {
   50% {
   -ms-transform: rotate(360deg) scale(0.8);
   -webkit-transform: rotate(360deg) scale(0.8);
   transform: rotate(360deg) scale(0.8);
  }
}
 @keyframes animate {
   50% {
   -ms-transform: rotate(360deg) scale(0.8);
   -webkit-transform: rotate(360deg) scale(0.8);
   transform: rotate(360deg) scale(0.8);
  }
}