ConvioAPI.js is no longer supported by Blackbaud and has cross domain issues.

One option that many clients find helpful is luminateExtend.js. luminateExtend was created specifically to address some of the cross domain issues present with ConvioAPI.js. luminateExtend is a free third party resource provided as-is and without warranty. Blackbaud does not support luminateExtend, but many clients have found success with it and the Blackbaud Community can be a great resource to find help for luminateExtend.

You can find luminateExtend at the GitHub repository.