<!DOCTYPE html>
<html>
    <head>
        <title>Escalator</title>
        <meta charset="utf-8" />
        <style>
            * { padding: 0; margin: 0; }
            canvas { display: block; margin: 0 auto; }
        </style>
    </head>
    <body>
        <canvas id="canvas"></canvas>
        <script src="js/escalator.js"></script>
    </body>
</html>