自动跳转

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>自动跳转</title>
    <style>
        p {
            text-align: center;
            color: black;
            font-family: 宋体;
        }

        p span {
            color: red;
            font-family: 宋体;
        }

    </style>
</head>
<body>
<p>
    <span id="time">5</span>秒之后，自动跳转到python3文档
</p>

<p>
    <a href="https://docs.python.org/zh-cn/3/" id="jumping">点击立刻跳转</a>
</p>
<script>
    var sec = 5;
    time = document.getElementById("time");
    var m = setInterval(countdown, 1000)


    function countdown() {
        if (time.innerHTML == 0) {

            clearInterval(m);
            location.href = 'https://docs.python.org/zh-cn/3/';

        } else {
            sec -= 1;
            time.innerHTML = sec;
        }


    }
    
</script>
</body>
</html>