[systoll]

The CSS Object Model.

HTML comments are basically just a HTML tag that isn't rendered. Tools that 'compile' the HTML code into a document tree, including browsers, preserve comments as nodes without any extra effort.

CSS comments can go anywhere:

    /*wow*/ .selector /*x*/ {animation /*z*/: 2s /*z*/ linear /*z*/ bounce;}

Tools that transform/parse CSS can either: 1. Strip comments before parsing, meaning anything based on the parsed version will lose the comments. 2. Dedicate a disproportionate amount of complexity to retaining the comments, and still not really have a good way to handle them through edits/transformations.

[yread]

But if it's valid CSS it has to be representable in AST/object model? It's a comment, it can't have any child nodes, it doesn't depend on anything - pretty trivial. And if it's in the tree you can transform it with proper tools. If you are transforming CSS you have to write a proper parser and not just a bunch of regexes

EDIT: also why is it useful to have comments in the object model in the first place? To access them from js?

[nialse]

Round-tripping to CSS and keeping information that may be useful to the user if they would inspect the content I would presume.

A similar issue is CDATA in XML which is not retained when round-tripped. Very annoying, but in line with the spec.