stroke/strokeWeight not defined in js page

I’m a super beginner with Javascript sorry if the question is a bit silly but I’ve copied this code from a tutorial and it doesn’t work at all when I look at the html page

stroke('green');
strokeWeight(20);
fill(0, 210, 247);

draw = function() {
ellipse(mouseX, mouseY, 30, 30);
}

Looking at the ispection tool it says “strokeWeight not defined”

Uncaught ReferenceError: strokeWeight is not defined
at theme.js:1:1

I tried to put stroke before strokeWeight and this time it says “stroke not defined”

Uncaught ReferenceError: stroke is not defined
at theme.js:2:1

I must be missing something