JSFiddle - React, Tailwind, and code Playground

HTML

<input type="button" value="Start" onclick="timedCount()" />
<input type="text" id="txt" />

<script type="text/javascript">
var seconds = 0;

function timedCount() {
    $("#txt").val(seconds);
    seconds += 1;
    setTimeout("timedCount()",1000);
}
</script>