JSFiddle - React, Tailwind, and code Playground

HTML

<body>
<input type=text id='t1' size='10'>
<span id='ct' ></span>


</body>

JavaScript

display_c();
function display_c(){
    setInterval(function(){display_ct()}, 3000);
}

function display_ct() {
    console.log('test');
    var strcount;
    var dt = new Date();
    var time = dt.getHours() + ":" + dt.getMinutes() + ":" + dt.getSeconds();
    
    document.getElementById('t1').value = time;
    tt=display_c();
}