JavaScript: Underscore Serialize JSON

gistfile1.js

_.mixin({
    serialize: function (obj) {
        var urlParams = _.map(obj, function (val, key) {
            var value = (_.isObject(val)) ? JSON.stringify(val) : String(val);
            return String(key) + '=' + value;
        });
        return urlParams.join('&');
    }
});