Untitled

<html>
<head>
    <title>Addition Andy</title>
</head>

<body>
    <input type="number" id="val1" placeholder="Valeur 1" required />
    <input type="number" id="val2" placeholder="Valeur 2" required />
    <button id="calcul" onclick="calcul();">Additionner</button>

    <script type="text/javascript">
           function calcul() {
            var val1 = parseInt(document.getElementById('val1').value);
            var val2 = parseInt(document.getElementById('val2').value);
            var resultat = val1+val2;
            alert('Le résultat de ' + val1 + ' + ' + val2 + ' est ' + resultat);
          }
    </script>
</body>

</html>