JS - setInterval & setTimeout.html

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>

    <button>DETENER PROCESO ASÍNCRONO</button>
    <br>
    <span>0</span>

    
    <script>


/*
        // setTimeout & clearTimeout
        var modal = setTimeout(function(){
            alert("DAME TU EMAIL AHORA")
        }, 5000)

        
        var buttons = document.getElementsByTagName('button')

        buttons[0].onclick = function(){
            console.log("Timeout cleared")
            clearTimeout(modal)
        }
*/


/* 
        // setInterval & clearInterval
        var seconds = 0;
        var counter = setInterval(function(){

            seconds++
            document.querySelector('span').textContent = seconds;

        }, 1000)

        var buttons = document.getElementsByTagName('button')

        buttons[0].onclick = function(){
            console.log("Interval cleared")
            clearInterval(counter)
        }
 */


    </script>
</body>
</html>