Can anyone explain why files cant be uploaded using AJAX?

Question

I have read many articles etc that attempt to explain why a file (e.g. attachment etc) cannot be uploaded via AJAX (atleast without some \'tricks\' behind the scene).

Ca

Answer 1

They can. It is XMLHttpRequest that can't be used to upload files. (But Ajax is more than XHR)

This is because, for security reasons, JavaScript can't read from the file system, so it can't get the file to hand to XHR.