Recursive x4 loop.js

var password = "";

function generateKeys(i, j, k, l, n) {
    if (i == n) {
        return;
    }

    password = i + "" + j + "" + "" + k + "" + l;

    if (l < n) {
        l++;
    }

    if (l == n) {
        k++;
        l = 0;
    }

    if (k == n) {
        k = 0;
        j++;
    }

    if (j == n) {
        j = 0;
        i++;
    }
    
    generateKeys(i, j, k, l, n);
}

generateKeys(0, 0, 0, 0, 10);