使用Ajax的时区

I have this Code in ajax which automatically pulls country and related state & city from js file.

I want to add Time-Zone to the related country/state/city.

Is there any better alternative way to get time-zone of the user performing sign-up?

Following is the code, Thanks

 <select name="country" class="countries" id="countryId">
     <option value="">Select Country</option>
 </select>
 <select name="state" class="states" id="stateId">
     <option value="">Select State</option>
 </select>
 <select name="city" class="cities" id="cityId">
     <option value="">Select City</option>
 </select>
 <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
 <script src="http://lab.iamrohit.in/js/location.js"></script>