javascript实现background 定时循环随机背景图

var bodyBgs = [];
bodyBgs[0] = "https://ww1.sinaimg.cn/large/87c01ec7gy1fshdwv00e9j211y0lcjs7.jpg";
bodyBgs[1] = "https://ww3.sinaimg.cn/large/87c01ec7gy1fshdwv56rfj21hc0u0n05.jpg";
bodyBgs[2] = "https://ww3.sinaimg.cn/large/87c01ec7gy1fshdwv5u70j21hc0u0n04.jpg";
bodyBgs[3] = "https://ww4.sinaimg.cn/large/87c01ec7gy1fshdwv8wc2j21hc0u0q5d.jpg";
bodyBgs[4] = "https://ww1.sinaimg.cn/large/87c01ec7gy1fshdwva5i5j21hc0u0q66.jpg";
bodyBgs[5] = "https://ww4.sinaimg.cn/large/87c01ec7gy1fshdwvjc6rj21hc0u0tnw.jpg";
bodyBgs[6] = "https://ww1.sinaimg.cn/large/87c01ec7gy1fshdwvw3hsj21hc0u044j.jpg";
bodyBgs[7] = "https://ww4.sinaimg.cn/large/87c01ec7gy1fshdww034zj21hc0u0jvv.jpg";
bodyBgs[8] = "https://ww4.sinaimg.cn/large/87c01ec7gy1fshdww0q12j21hc0u0tbu.jpg";
bodyBgs[9] = "https://ww1.sinaimg.cn/large/87c01ec7gy1fshdww62pdj21hc0u07b7.jpg";
bodyBgs[10] = "https://ww1.sinaimg.cn/large/87c01ec7gy1fshdww8nc0j21hc0u0wjv.jpg";
setInterval('Getbg();', 1000);
function Getbg(){
  var randomBgIndex = Math.round( Math.random() * 10 );
  //输出随机的背景图
  document.body.style.background="#9E9E9E url("+ bodyBgs[randomBgIndex] +") no-repeat ";
}