Thanks - that is good to know ... So I went into Classilla Preferences > Advanced > Scripts & Plugins. This is where the JavaScript settings appear to be.
However, I'm not seeing a way to globally enable them. Instead, the default appears to be that JavaScript is enabled for 'Navigator', and not enabled for 'Mail & Newsgroups'. Also, everything in the 'Allow scripts to' section is checked.
Also, there is this text: You must enable JavaScript for sites that you trust. To do so, click the S in the lower right of the current browser window
It seems these settings should already be correct, so I went back to
https://files.secureserver.net/0fSxARWHb8bA7P , clicked the "S" icon in the lower right corner of the browser, and followed the prompts (while leaving all settings at default) to enable JavaScript.
I then entered the password, clicked "Unlock", and the page was returned as would be expected. Also, clicking the 'Down' arrow icon does display the options ... except the 'Download' option was greyed out.
So I tried clicking the file link, but that didn't do anything .... Except that when I tried clicking the 'Down' arrow again, it didn't actually work now.
Anyway, at least this experience got me closer to download functionality, and perhaps it will be helpful in further debugging whatever is going on.
- Jim