JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html>
<head>
	<style>
    	* { font: 17px Calibri; }
    </style>
</head>
<body>
    <h3>Enter some values in the text to enable the button!</h3>
    <input type="text" id="txt" onkeyup="manage(this)" />
    <input type="submit" id="btSubmit" disabled />
</body>

<script>
	function manage(txt) {
        var bt = document.getElementById('btSubmit');
        if (txt.value != '') {
            bt.disabled = false;
        }
        else {
            bt.disabled = true;
        }
    }    
</script>
</html>