`language-js` also results in class `javascript` being applied

Repurposing this issue for the larger question/problem that it has brought up as mentioned in the comments below at:

https://github.com/highlightjs/highlight.js/issues/3023#issuecomment-787105999

Summary:

• language-js will also apply the javascript class
• language-javascript will NOT apply the javascript class
• some themes require un-prefixed class names to work properly (ie they apply per language themes)

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Describe the issue When I add the “language-php” class to the code element, the coloring is okay, but it adds an extra php tag. If I don’t give a class, it adds the php class and there is no problem.

Which language seems to have the issue? Only php, i haven’t seen such problem in other languages

Are you using highlight or highlightAuto? highlightAll

Sample Code to Reproduce You can take a look at the php block. Other languages ​​seem to be fine.

Expected behavior When we add the “language-php” class to the code element, it should not add the extra php tag.

[joshgoebel]

@Hirse CCing you since you’ve done some theme work.

[joshgoebel]

Part of the problem is I’m not sure there is any spec here at all. hljs-[name] would be the safest choice from a “do not conflict with other class names” perspective. But then we have a problem if a new language would ever overlap with a highlighting class… so now you’re back to hljs-language-[name]… a bit of a mouthful, but precise enough.

but it might be nice to have the language available as a CSS class for third-party themes.

One can also easily do this with a one-line plugin… should we perhaps just let those who wish to have such things do it themselves?

Example:

https://github.com/highlightjs/highlight.js/blob/main/docs/plugin-recipes.rst#data-language

CC @allejo

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So I’m kind of leaning towards:

• hljs-language-[grammar name] precise and hopefully future proof.
• Simply do not add a class by default at all, refer people to one line plugin recipe.

Don’t feel I have a strong preference. Either would be a breaking change so this needs to be decided before v11.