Set random background image from an array options.

JavaScript

const backgroundOptions = [
        'https://images.pexels.com/photos/36671775/pexels-photo-36671775.jpeg',
        'https://images.pexels.com/photos/17541770/pexels-photo-17541770.jpeg',
        'https://images.pexels.com/photos/36408889/pexels-photo-36408889.jpeg',
    ];
    function pickRandomNumber(min, max){
        let randomNumber = Math.random();
        let middleNumber = randomNumber * (max - min + 1) + min;
        let roundedNumber = Math.floor(middleNumber);
        return roundedNumber;
    }
    function pickRandomArrayItem(array){
        let randomArrayIndex = pickRandomNumber(0, array.length - 1);
        return array[randomArrayIndex];
    }
    function setRandomBackground(targetElement = document.body){
        let randomOption = pickRandomArrayItem(backgroundOptions);
        targetElement.style.backgroundImage = `url('${randomOption}')`;
    }
    setRandomBackground(document.body);