How do you get a random value for a variable in JavaScript? [closed]

Hey so im making an ambient DVD like animation, and i have 3 circles/DVD logos for this setup, i wanna set it’s initial position to be random on a 100% width and 100vh height container (fullscreen) Here’s my current setup:

const container = document.querySelector('.background-container');
const orange = document.querySelector('.circ-o');
const lime = document.querySelector('.circ-l');
const green = document.querySelector('.circ-g');
const FPS = 30;

// Orange circle moving velocity variables
let xPositionO = 10;
let yPositionO = 10;
let xSpeedO = 5;
let ySpeedO = 5;
// Lime circle moving velocity variables
let xPositionL = 10;
let yPositionL = 10;
let xSpeedL = 5;
let ySpeedL = 5;
// Green circle moving velocity variables
let xPositionG = 10;
let yPositionG = 10;
let xSpeedG = 5;
let ySpeedG = 5;

function update(){
    orange.style.left = xPositionO + 'px';
    orange.style.top = yPositionO + 'px';
    lime.style.left = xPositionL + 'px';
    lime.style.top = yPositionL + 'px';
    green.style.left = xPositionG + 'px';
    green.style.top = yPositionG + 'px';
}

setInterval(() => {
    if(xPositionO + orange.clientWidth >= window.innerWidth || xPositionO <= 0){
        xSpeedO = -xSpeedO;
    }
    if(yPositionO + orange.clientWidth >= window.innerWidth || yPositionO <= 0){
        ySpeedO = -ySpeedO;
    }
    if(xPositionL + lime.clientWidth >= window.innerWidth || xPositionL <= 0){
        xSpeedL = -xSpeedL;
    }
    if(yPositionL + lime.clientWidth >= window.innerWidth || yPositionL <= 0){
        ySpeedL = -ySpeedL;
    }
    if(xPositionG + green.clientWidth >= window.innerWidth || xPositionG <= 0){
        xSpeedG = -xSpeedG;
    }
    if(yPositionG + green.clientWidth >= window.innerWidth || yPositionG <= 0){
        ySpeedG = -ySpeedG;
    }
    xPositionO += xSpeedO;
    yPositionO += ySpeedO;
    xPositionL += xSpeedL;
    yPositionL += ySpeedL;
    xPositionG += xSpeedG;
    yPositionG += ySpeedG;
    update();
//1000ms divided by FPS constant
}, 1000/FPS)

I set all the xPosition and yPosition of all the circle to start at 10 and i then added a ‘px’ unit in the update function which will be executed each 1000/30ms, each time the 3 circles/DVD logos hit the border of the container, it would then set its speed to a negative value, making it look as if it is bouncing from the borders

Any help on this would be greatly appreciated!