我这样不可以吗
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1">
<title></title>
</head>
<span id="r">5</span>
<body>
<script type="text/javascript">
var i =document.getElementById("r");
setTimeout(i.innerHTML="4",3000);
</script>
</body>
</html>
