Javascript

<style>

    #current_date_time{

        height: 50px;

        width: 200px;

        background-color: blueviolet;

        border: 10px solid black;

        border-radius: 5px;

        font-size: 45px;

        text-align: center;

    }

</style>

<div id="current_date_time"></div>

<script>

// console.log(mydate)

// console.log(mydate.getFullYear())

// console.log(mydate.getMonth())

// console.log(mydate.getDate())

// console.log(mydate.getDay())

// console.log(mydate.getMinutes())

// console.log(mydate.getHours())

// console.log(mydate.getSeconds())

setInterval(()=>{

    var mydate = new Date();

   var ct =  mydate.getHours()+':'+mydate.getMinutes()+':'+mydate.getSeconds()

   document.getElementById('current_date_time').innerHTML = ct;

},1000)

</script>