function keys(obj) {
        if (!Object.keys) {
            var objKeys = [];
            for (var i in obj) {
                if (obj.hasOwnProperty(i)) {
                    objKeys.push(i);
                }
            }
            return objKeys;
        } else {
            return Object.keys(obj);
        }
    }
Shim for the Object.keys() method which does not exist in IE < 9
@param obj
@returns {Array}