frommapfile.html

<!DOCTYPE html>
<html>
    <head>
        <link href="sotesmap.css" rel="stylesheet" type="text/css">
        <style>
        </style>
        <script src="sotesconsts.js" type="text/javascript"></script>
        <script src="sotesmapfile.js" type="text/javascript"></script>
        <script>
            const FR = new FileReader
            const convert = () => {
                FR.readAsArrayBuffer(document.querySelector('input').files[0])
            }
            FR.onload = () => {
                window.map = MapFile.displayData(document.querySelector('section'), FR.result)
            }
        </script>
    </head>
    <body>
        <input type="file" onchange="convert()" />
        <hr>
        <section>
            <div class="lds-default"><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div></div>
        </section>
    </body>
</html>