function perms(data) {
    if (!(data instanceof Array)) {
        throw new TypeError("input data must be an Array");
    }

    data = data.slice();  // make a copy
    var permutations = [],
        stack = [];

    function doPerm() {
        if (data.length == 0) {
            permutations.push(stack.slice());
        }
        for (var i = 0; i < data.length; i++) {
            var x = data.splice(i, 1);
            stack.push(x);
            doPerm();
            stack.pop();
            data.splice(i, 0, x);
        }
    }

    doPerm();
    return permutations;
}

var input = "abcd".split('');

var result = perms(input);
for (var i = 0; i < result.length; i++) {
    result[i] = result[i].join('');
}
console.log(result);