原生JS实现Ripple水波纹按钮效果

 <ul id="nav">
  <li>
   <a href='#'>
    <span>首页</span>
   <span class="circle"></span>
   </a>
  </li>
  <li>
   <a href='#'>
    <span>我的</span>
   <span class="circle"></span>
   </a>
  </li>
  <li>
   <a href='#'>
    <span>更多</span>
   <span class="circle"></span>
   </a>
  </li>
 </ul>

 #nav {
 display: flex;
 }
 #nav li {
 position: relative;
 overflow: hidden;
 flex: 1;
 }
 li a {
  display: flex;
 flex-direction: column;
 justify-content: center;
 align-items: center;
 }

 .circle{
 position: absolute;
 background: rgba(86,187,247,.1);
 width: 1px;
 height: 1px;
 top:50%;
 left: 50%;
 border-radius: 50%;
 }
 .circle.act{
  animation: navCircle .4s;
 }

 @keyframes navCircle
 {
 from {transform: scale(0);border-radius: 50%;}
 to {transform:scale(200);border-radius: 50%;}
 }

 var li = document.getElementById('nav').querySelectorAll('li');
 var circle = document.getElementById('nav').querySelectorAll('.circle');
   for(var i=0,len = li.length;i<len;i++){
    ((i)=>{
    li[i].addEventListener('click',(e)=>{
     circle[i].setAttribute('class','circle act');
     circle[i].setAttribute('style','top:'+e.layerY+'px;left:'+e.layerX+'px');
    });

    li[i].addEventListener('touchend',()=>{
     circle[i].setAttribute('class','circle');
    })
    })(i)

   }