Wouldn't Python's use of whitespace to indicate nesting be annoying? JavaScript sometimes gets into pages embedded in script tags (as opposed to be being loaded from external files by script tags), and this is sometimes done by being echoed by server-side PHP or something similar.

Having to deal with getting the whitespace right while doing that could be annoying, and would also make the code much harder to read on the server side.

I think for this application, the more forgiving a language is about layout the better.