var arr = [1,2,3,4,5,6,7,8,9]

//第一種
function randomsort1 (arr) {
    for (let i = 0, len = arr.length; i < len; i++) {
        const ran = parseInt(Math.random() * len)
        const temp = arr[ran]
        arr[ran] = arr[i]
        arr[i] = temp
    }
    return arr
}

//第二種
function randomsort2 (arr) {
    const newarr = []
    while (arr.length) {
        const ran = parseInt(Math.random() * arr.length)
        newarr.push(arr[ran])
        arr.splice(ran, 1)
    }
    return newarr
}

//第三種
function randomsort3 (arr) {
    return arr.sort(() => Math.random() - 0.5)