form-submit.js neatly takes care of links that used to do a GET but now have to POST if they were targeting the current window, but links that were opening a new window/tab with target="_blank" can't. form-submit.js should look for data-targetwindow and set its value as the target attribute of the form. 

Inconveniently, Bootstrap 4 uses data-target as the CSS selector you are targeting, though Bootstrap 5 namespaces it as data-bs-target, so we shouldn't use data-target.

And possibly while form-submit.js is still young enough to change, we should namespace all the things that are aimed at it rather than at the form it creates, data-fs-method, data-fs-action, and then we could use data-fs-target, and someone who needs to submit a form with an input awkwardly named either method or action could get away with it.