I find this "code highlighting" very annoying. Can someone show me how to disable it on PHPStrom, and perhaps explain why this happens?
Here's an image of my Js/Jquery code on PHPStorm IDE:
In the WebStorm preferences go to Editor » Color & Fonts » General
choose Injected language fragment
from the list and turn off Background
chackbox.
It's hard to answer _why it happens) - it's just a preference. Maybe someone prefers to see injected code (the code in language other than the main one used in given file) clearly marked. For me, it's also a distraction, I have just turned it off inspired by your question ;)