unsupported.html

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title>Unsupported Browser</title>
        <meta http-equiv='content-type' content='text/html; charset=utf-8' />
        <meta name='viewport' content='initial-scale=1.0 maximum-scale=1.0'>
        <style>
        body {
            width:600px;
            margin:80px auto;
            font:normal 15px/25px sans-serif;
        }
        </style>
    </head>
    <body>
        <h1>Unsupported Browser</h1>
        <p>Sorry, the browser you're currently using is out of date and
        incompatible with geojson.io. Please <a href='http://abetterbrowser.org/'>upgrade
            to a modern browser in order to use the site.</p></p>
    </body>
</html>