代码如下：
<!DOCTYPE html><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>CSS3圆圈动画放大缩小循环动画效果</title><style>.dot {margin:150px auto;width:200px;height:200px;background-color:#E3E3E3;border-radius: 50%;box-shadow: 0 0 10px rgba(0,0,0,.3) inset;-webkit-animation-name:'ripple';/*动画属性名，也就是我们前面keyframes定义的动画名*/-webkit-animation-duration: 2s;/*动画持续时间*/-webkit-animation-timing-function: ease; /*动画频率，和transition-timing-function是一样的*/-webkit-animation-delay: 0s;/*动画延迟时间*/-webkit-animation-iteration-count: infinite;/*定义循环资料，infinite为无限次*/-webkit-animation-direction: alternate;/*定义动画方式*/}@keyframes ripple {0% {opacity:0.35;width:190px;height:190px;}100% {opacity: 0.2;width:250px;height:250px;}}</style></head><body><div class="dot"></div></body></html>
