Clone object (deep copy)

    var clone = function (obj) {
        var copy = obj instanceof Array? [] : {},
            key;

        for (key in obj) {
            if (obj.hasOwnProperty(key)) {
                if (typeof obj[key] === 'object') {
                    if (obj[key] instanceof Array) {
                        copy[key] = [];
                    } else {
                        copy[key] = {};
                    }

                    copy[key] = clone(obj[key]);
                } else {
                    copy[key] = obj[key];
                }
            }
        }

        return copy;
    };