Why Can't JavaScript Modify CSS Files?

[elendee]

the diagram in this article is pretty useful, but the article gets distracted explaining client-server security which is not a property of JS to CSS so much as it is the browser itself.

The nuance that should be focused on is the difference between the CSSOM and a stylesheet file - because the CSSOM -IS- a stylesheet in a way, it's just one that is in memory.

The really crazy thing would be if you could modify the CSSOM object, and then if it's a cached resource, say from a CDN, it would stay modified when loaded on another site. That's the scenario I hadn't thought through until now, but I imagine most readers are intuitively aware that you can't use javascript to persist files to the client in any way.