<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<script>
function traiter()
{
var i = 5;
i = i + 8;
alert("Message");
}
</script>
<input name="button" type="button" onClick="traiter()" value = "Bouton" >
</body>
</html>