Removing everything except capital letters using replace

Question

Yeah, I'm trying to remove everything except the capital letters, though it doesn't really seem to go well.

I used the following code,

String.replace(/(?![A-Z])./, '');

It doesn't seem to work properly, while it does work using PHP.

Answer 1

Add the global option at the end of the regex - see demo below:

console.log("AkjkljKK".replace(/(?![A-Z])./g, ''));