Produce cartesian product of a list of lists (javascript)

cartesianProduct.js

// Lives at: https://gist.github.com/3103615/
function cartesianProduct(xss) {
    if (!xss || xss.length < 1)
        return [];
    else {
        var head = xss[0];
        var tail = xss.slice(1);
        var result = [];
        for (var i = 0; i < head.length; i++) {
            var productOfTail = cartesianProduct(tail);
            if (productOfTail && productOfTail.length > 0) {
                for (var j = 0; j < productOfTail.length; j++) {
                    result.push([head[i]].concat(productOfTail[j]));
                }
            }
            else
                result.push([head[i]]);
        }
        return result;
    }
}

/*
 * Example use
var result = cartesianProduct([
        ['a', 'b'],
        ['1', '2', '3'],
        [{'a':0}, {'a': 1}],
        [{'b': 50}, {'b': 100}]
        ]);

console.log("Answer:");
console.log(result);
for (x in result) console.log(result[x]);
*/