<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
		<script type="text/javascript">
			function do_alert() {
				alert("js alert");
				console.log("Alert done");
			}
		</script>
    </head>
    <body>
        <input type="button" onclick="do_alert()" value="Show alert" id="button">
    </body>
</html>