yes, for server-side, but the problem still remain at client-side (so i proposed the  var extension = "." + this.acceptedTypes[i];  at line 309 of fileupload.js)...try it yourself to upload (in multiple upload mode) two files: one file with no extesions and the other with an extension that will be rejected, specyfing the acceptedTypes=",jpg,png" for example and see what happens...