https://github.com/knadh/dictpress/blob/master/site/static/main.js#L16C1-L17C1

.replace(/[^a-z\u00E0-\u00FC\s]/ig, '')

This regex replace is unnecessary for a default example template. I was confused why the search was not working and ending up in a HTTP authentication required page.

The form didn't look like it had a JS backing. One more suggestion is to remove the name attribute from the search form so that it is more clear. Why need a name if the form submission is actually handled by JS.