原文地址：https://www.jianshu.com/p/9b85fcac4ffc
//完整代码
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Loading</title>
</head>
<body>
<span id="loadin">-</span>
<script type="text/javascript">
function easy_loading(id){
var symbol = ['-', '\\', '|', '/'],
elem = document.getElementById(id),
i = 0;
(function __func() {
elem.innerHTML = symbol[i++ % 4];
setTimeout(__func, 200);
})();
}
easy_loading('loadin');
</script>
</body>
</html>