When using javascript sdk,
I download dropbox-sdk-js/examples/auth/index.html,
put Dropbox-sdk.min.js, styles.css, utils.js to the same folder,
modify these three file's location in index.html,
<head>
<title>Dropbox JavaScript SDK</title>
<link rel="stylesheet" href="styles.css">
<script src="Dropbox-sdk.min.js"></script>
<script src="utils.js"></script>
</head>
open index.html will see:

after click Authenticate:

after click allow:

Please help how the javascript sdk get the root file list after authentication?