STEPS TO REPRODUCE ERROR
STEP 1
Configure AsyncFileUpload with normal client (JavaScript) and server methods.
__On client functions__:
uploadError(sender, args) {..} and function uploadComplete(sender, args) {..}
_On server codebehind_:
AsyncFileUpload1_UploadedComplete(..) and AsyncFileUpload1_UploadedFileError(..)
On ASPX add a button than only do a Postback.
Now upload a large file (over 4 mbytes the default limit). After detected uploadError on Client JavaScript Function, the control display on red background color the name of the file.
STEP 2
Click on the Button to generate a Postback.
RESULT:
Automatically launch a new browser tab showing a URL querystring like this:
http://localhost/ImagesInGridViewDb/tImageUpload1.aspx___?AsyncFileUploadID=AsyncFileUpload1&rnd=0008577673175017342___
What is the mean of:
?AsyncFileUploadID=AsyncFileUpload1&rnd=0008577673175017342
See the image:
![Image](https://drive.google.com/file/d/0B7bumYZC90F0aXdHZVdhUktjMlU/edit?usp=sharing)