Not as yet. It's been discussed as something that we need to look at in the future, but a lot of hosted blog services have restrictions on JS, and for very good security reasons. Blogspot doesn't, which is why Blogspot is the host of choice for dodgy malware and spam pedlers.

The concerns are valid. My desire to use some JS in the sidebar is valid. Any ideas for squaring the circle welcome, if you're into development stuff. It's beyond my ability to fix, unfortunately, I barely comprehend some of the issues.