See this comment in the Stack Exchange sandbox. I quote it here:
Have a look at this JS code:
document.body.removeChild(document.body.appendChild(document.createElement('style')));If you manually type it into your browser console it will work, but copying and pasting from my comment will throw an error because Stack Exchange randomly adds
\u200ccharacters for no apparent reason. You can even manually type it in a comment on Stack Exchange, then copy and paste again, and it still won't work.