<html>
    <head>
        <script src="https://randojs.com/1.0.0.js"></script>
        <script>
            function showRandomNumber(){
                document.getElementById("myNumber").innerHTML = rando(9999, 99999);
            }
        </script>
        <style>
            #myNumber{
                font-size:100px;
                text-align:center;
                margin:50px auto;
                font-family:Arial, sans-serif;
            }
        </style>
    </head>
    <body onload="showRandomNumber();">
        <div id="myNumber"></div>
    </body>
</html>