window.addEventListener("keydown", function(event){
    if (event.code == "yourKeyCode"){
        console.log("Key pressed!");
        //something
    }
});

"yourKeyCode" you can check in this example (or find another on your language).

That's what I found online when I searched for it and I didn't understand so can you explain how it works

"window" is JS element which is all your browser page. "addEventListener" listens all events "keydown" (press key on keyboard) on this element (when mouse cursor is in the page). Then it runs function. In function we check code of this key (event.code) and if it`s true we do code in {}.

For example key Z has code "KeyZ", shift has code "ShiftRight" and "ShiftLeft". You should replace string "yourKeyCode" with needed you key code.

If you need check press key on concret element (some input, for example), you can use

yourElement.addEventListener("keydown", function...

"yourElement" you can get with

var yourElement = document.querySelector(".class-name")

"class -name" is name of your element class, or you can use # for get element by id (querySelector("#yourId");)

Ohhhhhh at first I just put "r" like this

window.addEventListener("keydown", function(event){
    if (event.code == "r"){
    	
        location.href = mw.util.getUrl(mw.config.get("wgPageName"), {action: "raw"});

    }
});

Also thank you

No, you should use "KeyR" for "r".

Yes that's what I did

I would use "keyup" in most cases rather than "keydown".

"keydown" fires when the key is pressed down, while "keyup" runs when the key is released. Also, in case the user holds the key down for longer time, "keydown" fires repeatedly while "keyup" is supposed to only fire once when the key is released.

I believe the "keyup" behavior is what most users would expect unless it's about typing text.

Thanks

Oh, yes, "keyup" is better.