SOURCE

let testArr = [5, 17, 1, 33, 2, 6, 20];
document.write(testArr + "<br/>");

function bubbleSort(arr) {
    let temp;
    for (let i = 0; i < arr.length; i++) {
        for (let j = 0; j < arr.length - 1; j++) {
            if (arr[j+1] < arr[j]) {
                temp = arr[j];
                arr[j] = arr[j+1];
                arr[j+1] = temp;
            }
        }
    }
    return arr;
}

document.write(bubbleSort(testArr));