// 冒泡排序
function sorT(arr) {
    for (var i = 0; i <= arr.length - 1; i++) {
        for (var j = 0; j <= arr.length - i - 1; j++) {
            if (arr[j] < arr[j + 1]) {
                var temp = arr[j+1];
                arr[j+1] = arr[j];
                arr[j] = temp;
            }
        }
    }
    return arr;
}
var str = sorT([7,45,2,342,1,34,51,2]);
console.log(str);