Rewriting attribute selectors is lossy

[jimmyfrasche]

Using div[id=a] instead of div#a is a valid technique for matching an id with lower specificity than the id selector.

Using div[class=a] is not the same as div.a. The former matches a div with only class a and no others.

This minification is not safe. It changes the semantics of the rules.

[tdewolff]

Thanks for the find. To be clear, only the minification for classes is unsafe or do you think the minification for ID's is unsafe too? A lower specificity could cause problems...

[jimmyfrasche]

They are both unsafe in that they change the intent of what was written. The lower specificity makes it easier to override in, say, a media query.