http://blog.csdn.net/LaoJiu_/...
不过是C++写的，话说写算法干嘛用js。。。。真的是。。至少会个c啊

Heap's Algorithm

function swap(index1, index2) {
    tmp = arr[index1];
    arr[index1] = arr[index2];
    arr[index2] = tmp;
}

function generate(int) {
    if (int === 1) {
        // Make sure to join the characters as we create  the permutation arrays
        order.push(arr.join(''));
    } else {
        for (var i = 0; i != int; ++i) {
            generate(int - 1);
            swap(int % 2 ? 0 : i, int - 1);
        }
    }
}

var order = [];
arr=['a', 'b', 'c', 'd'];
generate(arr.length);
console.log(order);