How is this new? We've had a Braintree client side library ("Braintree End-to-End Encryption Library") to do exactly this for at least a year. File is even called braintree.js.
Or was it in a "beta" and now this is a final release? Or am I missing something big here?
Braintree developer here. You're right that Braintree.js is based upon our end-to-end encryption library. While that's been out of beta for some time, it was strictly for encryption (that's literally the only thing it did).
In this iteration we've added some helper methods to the Braintree object that make it much easier, in our opinion, to encrypt your payment form. In the past, if you wanted to use our encryption library, you had to intercept the POST to your server with a custom onSubmit handler to encrypt the data. Now, it's as simple as giving the id of the form you wish to encrypt and substituting the "name" attribute on your form inputs with "data-encrypted-name".
Additionally, unlike our previous encryption library, we're now hosting the JavaScript in our datacenter using the same highly available infrastructure we built for our gateway. This makes it easier to get up and going when you're spiking out your integration.
Ultimately, we felt that these improvements justified re-branding the library, especially since we now recommend Braintree.js over Transparent Redirect. Transparent Redirect unfortunately made it kind of awkward if you wanted to do your own server-side validation on the form data or do anything with AJAX.
Thanks for the explanation. I've also been using v1.1.1 for a while now and the release notes weren't particular enlightening as to the differences. I don't plan on changing our workflow since it's working and tested, but I did change the link to the JS file from our servers to yours.
Or was it in a "beta" and now this is a final release? Or am I missing something big here?