learnJavaScript/clock.html at main · mikebars1995/learnJavaScript · GitHub

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<!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>
    <div id="clock">
        <span class="hour">hh</span>:<span class="min">mm</span>:<span class="sec">ss</span>
    </div>
    <button onclick="clockStart()">Start</button>
    <button onclick="clockStop()">Stop</button>

    <script>
        function update() {
            let clock = document.getElementById('clock')
            let date = new Date()
            let hours = date.getHours()
            if (hours < 10) hours = '0' + hours
            clock.children[0].innerHTML = hours

            let minutes = date.getMinutes()
            if (minutes < 10) minutes = '0' + minutes
            clock.children[1].innerHTML = minutes

            let seconds = date.getSeconds()
            if (seconds < 10) seconds = '0' + seconds
            clock.children[2].innerHTML = seconds
        }

        let timerId

        function clockStart() {
            timeId = setInterval(update, 1000)
            update()
        }

        function clockStop() {
            clearInterval(timerId)
            timerId = null
        }
    </script>
</body>

</html>