[jasondavies]

The text is in fact processed in the client, and is quite fast even for large corpora such as the whole Bible: http://www.jasondavies.com/wordtree/?source=kjv.txt&pref...

It attempts to access URLs directly but this only works if the server sends the appropriate CORS headers (hardly ever).

Otherwise, it falls back to using a proxy, which means the client only sees what the proxy sees. However, you can also paste raw text on the main page.

I could imagine modifying the bookmarklet so it lifts the text directly from the browser instead of just copying the URL. This would solve the proxy issue neatly and would also work for local-only or intranet sites, for which the proxy also fails.