I want to send [1, n) AJAX-requests to the server and after all have returned a result a modal dialog should be closed. $.when(a(), b(), c()) would be perfect,
$.when(a(), b(), c())
Call the functions and add their return values to an array. Then call $.when passing the array as argument like so:
$.when
$.when.apply($, array)
See Function.prototype.apply [MDN] for more information and my answer here for an extended example.