css3点击涟漪效果

代码如下：
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
  <style>
    @import url(http://fonts.googleapis.com/css?family=Roboto:400,300,100,500);
    html {
      background-color: #eeedef;
    }
    #container {
      position: absolute;
      top: 50%;
      left: 50%;
      margin-right: -50%;
      opacity: 0.9;
      transform: translate(-50%, -50%);
      -webkit-transform: translate(-50%, -50%);
      -moz-transform: translate(-50%, -50%);
    }
    .paper {
      background-color: #fffeff;
       500px;
      height: 100px;
      overflow: hidden;
      position: relative;
      margin-bottom: 16px;
      box-shadow: 0px 1px 2px 1px #d3d2d3;
      border-radius: 2px;
      transition: 0.1s ease-in;
      -webkit-user-select: none;
      -moz-user-select: none;
      -ms-user-select: none;
      user-select: none;
    }
    .paper:hover {
      cursor: pointer;
    }
    #num {
      font-family: 'Roboto', sans-serif;
      font-size: 28px;
      color: #999;
      text-align: center;
      margin-top: 32px;
    }
    .ripple {
      background-color: rgba(0, 0, 0, 0.45);
      border-radius: 100%;
      height: 100px;
       100px;
      margin-top: -90px;
      position: relative;
      -webkit-transform: scale(0);
      transform: scale(0);
    }
    .animate {
      -webkit-animation: ripple 0.4s linear;
      animation: ripple 0.4s linear;
    }
    @-webkit-keyframes ripple {
      100% {
        -webkit-transform: scale(12);
        transform: scale(12);
        background-color: transparent;
      }
    }
    @keyframes ripple {
      100% {
        -webkit-transform: scale(12);
        transform: scale(12);
        background-color: transparent;
      }
    }
  </style>
  <script src="http://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script>
  <script>
  $(document).ready(function() {
  $(".paper").mousedown(function(e) {
    var ripple = $(this).find(".ripple");
    ripple.removeClass("animate");
    var x = parseInt(e.pageX - $(this).offset().left) - (ripple.width() / 2);
    var y = parseInt(e.pageY - $(this).offset().top) - (ripple.height() / 2);
    ripple.css({
      top: y,
      left: x
    }).addClass("animate");
  });
});
  </script>
</head>
<body>
  <div id="container">
  <div class="paper">
    <p id="num">1</p>
    <div class="ripple"></div>
  </div>
</div>
</body>
</html>
View Code
效果如下图：