JavaScriptd動態產生下拉式選單

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<html lang="zh-TW">
<head>
    <meta charset="UTF-8">
    <title>index</title>
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<div align="center">
    時間： <select id="start_time" name="start_time"></select>
</div>
<script>
    //90ED_7FD4_5B87
    //https://www.facebook.com/groups/1403852566495675/permalink/2390650747815847/
    //動態產生下拉式選單的時間項目
    let objStartTime = document.getElementById("start_time");
    for (let hour = 0; hour <= 23; hour++) {
        for (let minute = 0; minute <= 30; minute += 30) {
            let str = `${hour.toString().padStart(2, '0')}：${minute.toString().padStart(2, '0')}`;
            // let str = hour.toString().padStart(2, "0") + "：" + minute.toString().padStart(2, "0");
            let objOption = new Option(str, str);
            objStartTime.add(objOption);
        }
    }
</script>
</body>
</html>