使用CSS实现按钮点击波纹效果

有的网站会为按钮添加点击波纹效果提升网站效果，我们可以简单实现一下：

主要借助::after伪类及CSS3中的transform和transition属性：
html:

<div class="container text-center">        <button class="btn btn-default ripple btn-lg">Button</button>        <button class="btn btn-default ripple btn-lg">Button with very long content</button></div>

.ripple {    position: relative;    //隐藏溢出的径向渐变背景    overflow: hidden;}.ripple:after {    content: "";    display: block;    position: absolute;    width: 100%;    height: 100%;    top: 0;    left: 0;    pointer-events: none;    //设置径向渐变    background-image: radial-gradient(circle, #666 10%, transparent 10.01%);    background-repeat: no-repeat;    background-position: 50%;    transform: scale(10, 10);    opacity: 0;    transition: transform .3s, opacity .5s;}.ripple:active:after {    transform: scale(0, 0);    opacity: .3;    //设置初始状态    transition: 0s;}

参考链接：https://mladenplavsic.github.io/css-ripple-effect/#
效果：

阿里的Ant Design按钮风格也可以以这个为模板来实现：

.ripple {    position: relative;    //此处不需要设置overflow:hidden,因为after元素需要溢出显示}.ripple:focus{    outline: none;}.ripple:after {    content: "";    display: block;    position: absolute;    //扩大伪类元素4个方向各10px    top: -10px;    left: -10px;    right: -10px;    bottom: -10px;    pointer-events: none;    background-color: #333;    background-repeat: no-repeat;    background-position: 50%;    opacity: 0;    transition: all .3s;}.ripple:active:after {    opacity: .3;    //设置初始状态    top: 0;    left: 0;    right: 0;    bottom: 0;    transition: 0s;}

效果：

代码地址：https://github.com/justforuse/interesting-effect-collection/tree/master/ripple-effect

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Google的Material Design风格的按钮除了有波纹效果，还会根据点击位置设置波纹中心，这就需要JS来介入了，可以参考这个demo：https://codepen.io/jh3y/pen/EKGXEY