This javascripts are optional but help you quickly add authy to your site and look great.

There are core functionalities:

1. Token input. The javascript adds the authy logo to the field.
2. Authy help toggle. A simple javascript toggle that you can add anywere to explain what authy is.
3. Client-sice cellphone verifier.
4. Country code dropdown with flags and autocomplete.

git clone git://github.com/authy/authy-javascripts.git

open example.html in chrome, safari or internet explorer.

This example shows how to use it.
Add form.authy.min.js, form.authy.css and images to your site.

Use the #id to add the functionality to the fields you want.

id="authy-token": For the token input during login
id="authy-help": A help tooltip you can use on login or register
id="authy-cellphone": When asking for user cellphone during
registreation/
id="authy-countries": Optional country dropdown during registration

You can fine the full API documentation in the official documentation page.