[juriansluiman]

I have used a similar tool [1] some time ago in PHP. The project hasn't been kept updated, but the idea of processing text/HTML and converting the right entities is pretty neat. At least the readability improves massively.

This project Typeset.js is slightly different as it adds additional markup and styles. For me, converting here's to here’s was enough for me back then.

[1]: https://github.com/scoates/lexentity

[Damin0u]

For PHP you can have a look at JoliTypo [1], much more up to date, tested, working for any style guide and using a real parser.

[1]: https://github.com/jolicode/jolitypo

Disclaimer: I'm the author, and I've tested them all.