hello溢出，请老师帮忙看下

来源：1-26 编程练习

星辰也伤风

2020-07-19 11:31:23

<!DOCTYPE html>
<html>

<head lang="en">
    <meta charset="UTF-8">
    <title>setInterval()</title>
    <style type="text/css">
        div {
            width: 300px;
            height: 300px;
            border: 1px solid #333;
        }
    </style>
</head>

<body>
    <input type="button" value="开始">
    <br><br>
    <div></div>
    <script type="text/javascript">
        //补充代码
        var box = document.getElementsByTagName("div")[0],
            btn = document.getElementsByTagName("input")[0];

        function blink() {
            box.innerHTML += "hello&nbsp;";
        };

        btn.onclick = function () {
            setInterval(blink, 1000);
        };
    </script>
</body>

</html>