Why not just "Javascript web app", or "browser-based Javascript app"?
As the comments have pointed out, just because you didn't write any server side code, it doesn't mean it's not a web app. So, "web app" actually does fit, but may be a little too vague for your purposes, due to the lack of server side code with the app itself, though technically, if you hook into any APIs at all, then someone had to write server side code somewhere, even if that someone wasn't you.
Calling it a "Javascript app" doesn't work, as there are cases where Javascript can be used to create applications that aren't actually web apps (Appcelerator Titanium Mobile, and Gnome 3 extensions come to mind).
On the same token, using "browser app" doesn't really work well, as browsers themselves can now host apps as extensions (such as the Chrome version of Angry Birds, or the Firebug Firefox extension, for example). Though, "browser-based Javascript app" could work, though it is a little wordy.
"Web tool" and "web script" might be able to work, but they're really vague (in my opinion). Likewise, "standalone webapp" doesn't mean much, either. Standalone from what? Does that mean it can run without a browser? Any webapp could be considered "standalone," if you think about it. "Client-only"? Again, seems rather vague, especially if you're dealing with non-technical people, or anyone who doesn't understand the client-server nature of the web.
"Pure Javascript", by itself, is generally in reference to the language (ie - Javascript without the use of frameworks or extensions like jQuery). A "pure Javascript web app" could be used, but seems a little wordy, and may provide inaccurate connotations of not using a JS framework.
Browser App? (Because it is no longerwebif it doesn't go out towebat least). – Dipan Mehta Jan 17 '12 at 7:00web APIsis that not going out toweb? But I like the term "browser app" - is it in use? – hippietrail Jan 17 '12 at 10:04HTMLandCSSwhich ought to make the both not pure, and not just scripts. And it's easy to imagine much more complex ones than mine. – hippietrail Jan 17 '12 at 10:07