如何获取系统时间分别进行提醒

img

已知script部分,如何编写出完整的代码,图片随意插入的情况下,获取系统时间分别进行提醒


<!DOCTYPE html>
<html lang="en">

    <head>
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Document</title>
    </head>

    <body>
        <script>
            // 0---23
            var hourNum = new Date().getHours();
            if (hourNum <= 12) {
                document.write("上午好")
            } else if (hourNum <= 18) {
                document.write("下午好")
            } else {
                document.write("晚上好")
            }
        </script>
    </body>

</html>

new Date().getHours()

https://www.jb51.net/w3school/js/jsref_getHours.htm

getHours 然后判断就行