As Andrew Kondratev has pointed out on https://github.com/apache/wicket/pull/255, we can use FormData to send multipart data via Ajax. This makes the current iframe workaround obsolete.
- real Ajax !!1!!!
- we can drop a lot of code in wicket-ajax-jquery.js
- users can use Wicket.Ajax to send files as extra parameters, as requested in pull request #255
FormData is supported in Edge and IE 10. I'm not sure whether we still support older browsers, but as fallback users can
- continue using Wicket 7 (supported for the next years)
- switch to non-Ajax uploads
- use a polyfill for FormData (several available on github)