Connect Form via Ajax to Drip JS API

Request details We have an embedded subscription form on our site that we'd like connected to account on [login to view URL] for newsletter subscriptions. We'd don't want the form to redirect and instead submit "behind the scenes" via Drip's JS API ([login to view URL]) as drip does not support CORS. We'd like the solution to provide flexibility in how the subscriber is "joined" into Drip, i.e., tagging, additional form fields, workflows, etc., and the solution should provided for robust error handling and reporting. You can get an idea as to where we are with a prior attempt here: onlysheets.com. Upon successful submission, or error, confirmation should occur without any redirects. Deliverables JS API file for us to host and connect to the existing form.