基于Canvas与定时器实现动态加载动画

<!DOCTYPE html>
<html>
<head lang="en">
  <meta charset="UTF-8">
  <title></title>
  <style>

  </style>
</head>
<body>
  <canvas id="canvas" width="500" height="500">你的浏览器不支持canvas技术</canvas>
  <script>
    var c=document.getElementById('canvas');
    var ctx= c.getContext('2d');
    ctx.translate(c.width/2, c.height/2);
    //首先绘制8个静态环绕的圆形
    function create() {
      for (var i = 1; i < 9; i++) {
        if (i==1) {
          ctx.beginPath();
          ctx.arc(0, -30, 5, 0, 2 * Math.PI);
          ctx.fillStyle='#f0f';
          ctx.fill();
        }else{
          ctx.beginPath();
          ctx.arc(0, -30, 5, 0, 2 * Math.PI);
          ctx.strokeStyle ='#000';
          ctx.stroke();
        }
        ctx.rotate(Math.PI * 45 / 180);
      }
    }
    //定时转动
    setInterval(function(){
      ctx.clearRect(-c.width/2,-c.height, c.width, c.height);
      create();
      ctx.rotate(Math.PI*45/180);
    },300);
    //定时关闭加载
    setTimeout(function(){
     c.style.display='none';
   },12200);
    //
  </script>
</body>
</html>