js点击按钮实现水波纹效果代码（CSS3和Canves）

近来看到个不错的按钮点击效果，当点击时产生一次水波涟漪效果，挺好玩的，于是简单的实现了下(没考虑低版本浏览器兼容问题) 

先看看效果吧，如下图（录制gif软件有点渣，看起来卡卡的...）

这种效果可以由元素内嵌套canves实现，也可以由css3实现。 

Canves实现 

网上摘了一份canves实现的代码，略微去掉了些重复定义的样式并且给出js注释，代码如下 

html代码：<a class="btn color-1 material-design" data-color="#2f5398">Press me!</a>

css代码： 

* {
 box-sizing: border-box;
 outline: none;
}
body {
 font-family: 'Open Sans';
 font-size: 100%;
 font-weight: 300;
 line-height: 1.5em;
 text-align: center;
}
.btn {
 border: none;
 display: inline-block;
 color: white;
 overflow: hidden;
 margin: 1rem;
 padding: 0;
 width: 150px;
 height: 40px;
 text-align: center;
 line-height: 40px;
 border-radius: 5px;
}
.btn.color-1 {
 background-color: #426fc5;
}
.btn-border.color-1 {
 background-color: transparent;
 border: 2px solid #426fc5;
 color: #426fc5;
}
.material-design {
 position: relative;
}
.material-design canvas {
 opacity: 0.25;
 position: absolute;
 top: 0;
 left: 0;
}
.container {
 align-content: center;
 align-items: flex-start;
 display: flex;
 flex-direction: row;
 flex-wrap: wrap;
 justify-content: center;
 margin: 0 auto;
 max-width: 46rem;
}

js代码 ：

var canvas = {},
  centerX = 0,
  centerY = 0,
  color = '',
  containers = document.getElementsByClassName('material-design')
  context = {},
  element = {},
  radius = 0,
  // 根据callback生成requestAnimationFrame动画
  requestAnimFrame = function () {
   return (
    window.requestAnimationFrame    || 
    window.mozRequestAnimationFrame  || 
    window.oRequestAnimationFrame   || 
    window.msRequestAnimationFrame   || 
    function (callback) {
     window.setTimeout(callback, 1000 / 60);
    }
   );
  } (),
  // 为每个指定元素生成canves
  init = function () {
   containers = Array.prototype.slice.call(containers);
   for (var i = 0; i < containers.length; i += 1) {
    canvas = document.createElement('canvas');
    canvas.addEventListener('click', press, false);
    containers[i].appendChild(canvas);
    canvas.style.width ='100%';
    canvas.style.height='100%';
    canvas.width = canvas.offsetWidth;
    canvas.height = canvas.offsetHeight;
   }
  },
  // 点击并且获取需要的数据，如点击坐标、元素大小、颜色
  press = function (event) {
   color = event.toElement.parentElement.dataset.color;
   element = event.toElement;
   context = element.getContext('2d');
   radius = 0;
   centerX = event.offsetX;
   centerY = event.offsetY;
   context.clearRect(0, 0, element.width, element.height);
   draw();
  },
  // 绘制圆形，并且执行动画
  draw = function () {
   context.beginPath();
   context.arc(centerX, centerY, radius, 0, 2 * Math.PI, false);
   context.fillStyle = color;
   context.fill();
   radius += 2;
   // 通过判断半径小于元素宽度，不断绘制 radius += 2 的圆形
   if (radius < element.width) {
    requestAnimFrame(draw);
   }
  };

init();

CSS3实现 

接下来就是纯手打的代码了...觉得还是css3实现的方便些，可能是css写习惯了... 

html代码 

<a class="waves ts-btn">Press me!</a>

css代码 

.waves{
  position:relative;
  cursor:pointer;
  display:inline-block;
  overflow:hidden;
  text-align: center;
  -webkit-tap-highlight-color:transparent;
  z-index:1;
}
.waves .waves-animation{
  position:absolute;
  border-radius:50%;
  width:25px;
  height:25px;
  opacity:0;
  background:rgba(255,255,255,0.3);
  transition:all 0.7s ease-out;
  transition-property:transform, opacity, -webkit-transform;
  -webkit-transform:scale(0);
  transform:scale(0);
  pointer-events:none
}
.ts-btn{
  width: 200px;
  height: 56px;
  line-height: 56px;
  background: #f57035;
  color: #fff;
  border-radius: 5px;
}

js代码 

document.addEventListener('DOMContentLoaded',function(){

   var duration = 750;

   // 样式string拼凑
   var forStyle = function(position){
    var cssStr = '';
    for( var key in position){
     if(position.hasOwnProperty(key)) cssStr += key+':'+position[key]+';';
    };
    return cssStr;
   }

   // 获取鼠标点击位置
   var forRect = function(target){
    var position = {
     top:0,
     left:0
    }, ele = document.documentElement;
    'undefined' != typeof target.getBoundingClientRect && (position = target.getBoundingClientRect());
    return {
      top: position.top + window.pageYOffset - ele.clientTop,
      left: position.left + window.pageXOffset - ele.clientLeft
    }
   }

   var show = function(event){
    var pDiv = event.target,
     cDiv = document.createElement('div');
    pDiv.appendChild(cDiv);
    var rectObj = forRect(pDiv),
     _height = event.pageY - rectObj.top,
     _left = event.pageX - rectObj.left,
     _scale = 'scale(' + pDiv.clientWidth / 100 * 10 + ')';
    var position = {
     top: _height+'px',
     left: _left+'px'
    };
    cDiv.className = cDiv.className + " waves-animation",
    cDiv.setAttribute("style", forStyle(position)),
    position["-webkit-transform"] = _scale,
    position["-moz-transform"] = _scale,
    position["-ms-transform"] = _scale,
    position["-o-transform"] = _scale,
    position.transform = _scale,
    position.opacity = "1",
    position["-webkit-transition-duration"] = duration + "ms",
    position["-moz-transition-duration"] = duration + "ms",
    position["-o-transition-duration"] = duration + "ms",
    position["transition-duration"] = duration + "ms",
    position["-webkit-transition-timing-function"] = "cubic-bezier(0.250, 0.460, 0.450, 0.940)",
    position["-moz-transition-timing-function"] = "cubic-bezier(0.250, 0.460, 0.450, 0.940)",
    position["-o-transition-timing-function"] = "cubic-bezier(0.250, 0.460, 0.450, 0.940)",
    position["transition-timing-function"] = "cubic-bezier(0.250, 0.460, 0.450, 0.940)",
    cDiv.setAttribute("style", forStyle(position));
    var finishStyle = {
     opacity: 0,
     "-webkit-transition-duration": duration + "ms",  // 过渡时间
     "-moz-transition-duration": duration + "ms",
     "-o-transition-duration": duration + "ms",
     "transition-duration": duration + "ms",
     "-webkit-transform" : _scale,
     "-moz-transform" : _scale,
     "-ms-transform" : _scale,
     "-o-transform" : _scale,
     top: _height + "px",
     left: _left + "px",
    };
    setTimeout(function(){
     cDiv.setAttribute("style", forStyle(finishStyle));
     setTimeout(function(){
      pDiv.removeChild(cDiv);
     },duration);
    },100)
   }
   document.querySelector('.waves').addEventListener('click',function(e){
    show(e);
   },!1);
  },!1);

就这些，原理也简单，获取点击位置 >  添加样式   顺便，中秋快乐~