test.html

<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="content-type" content="text/html; charset=UTF-8" />
        <script type="application/javascript" src="scheduler.js"></script>
        <script type="application/javascript">
            var scheduler = new Scheduler()

            scheduler.add(                "https://api.stackexchange.com/2.2/info?site=stackoverflow",
                function (text){
                    alert(
                        JSON.parse(text).items[0].new_active_users
                    )
                },
                "GET"
            )

            scheduler.add(
                "https://api.github.com/zen",
                function (text){
                    console.log(text)
                },
                "GET"
            )

            console.log(scheduler.status())
            window.setTimeout(
                function(){
                    console.log(scheduler.status())
                }, 500
            )
        </script>
    </head>
    <body></body>
</html>