I just tested it with Chrome Version 83.0.4103.97 (build official) (64 bits) amn it worked.

I updated Chrome on the same machine to 83.0.4103.116 (official build) (64 bits) and it stopped working.

So, I presume Google Chrome 83.0.4103.116 is the trouble maker.

Seem to work one time, then it stop working.
I made this test form, I was able to upload a file at first attempt, but not working second and third try.
https://limesurvey.criugm.qc.ca/index.php/662578?lang=fr

Do not have any issues - cannot reproduce (played with your installation)

I will ask my colleagues for further testing.

LE: Meanwhile, can you please upgrade to the latest LTS release and try again?

I will update to limesurvey3.22.21+200622 tonight, and let you know.

I can easily reproduce the error:
Windows 10
Update your Chrome Browser to the latest Version 83.0.4103.116 and restart Chrome
Open : https://limesurvey.criugm.qc.ca/index.php/662578?lang=fr
Try upload any pdf file.
Sometimes it work the first time, but not on the second or third attempt.

Ok, so I cannot reproduce it on the latest Chrome (83.0.4103.116) - I use Ubuntu 20.04.
Will wait for one of my Windows colleagues to check the issue.
The ticket is marked as private -> can i take the "private" status out?

Yes, you take the "private" status out.
tx

I cannot reproduce the problem either on ubuntu 18 (Chrome 83.0.4103.116).
But I have the same problem on Android 9 (Chrome 83.0.4103.106).
It works well on Firefox (Windows, Ubuntu and Android).

I just updated to LimeSurvey Version 3.22.21+200622
Problem is still present.

Tested the issue on the latest chrome (Version 83.0.4103.116 (Official Build) (64-bit)), i am not able to upload the file anyways.
Please refer the attachement for more details

Related ?
https://bugs.limesurvey.org/view.php?id=16395

Sometimes it work the first time, but not on the second or third attempt.

https://bugs.limesurvey.org/view.php?id=16395#c58366

Issue moved to confirmed

For information :
Fedora/Linux
Version 83.0.4103.116 (Build officiel) (64 bits)

It's OK.

Related to operating system.

From what I was able to see (and understand), the issue happens because of some false positive load events of the iframe.
I mean some load events are triggered for the iframe (example for the about:blank doc) while they should be ignored.

There are already some filters, so I am adding a new one.

https://github.com/LimeSurvey/LimeSurvey/pull/1445

We could be checking the src of the iframe as an extra filtering layer.

We could be checking the src of the iframe as an extra filtering layer.

We must move to something without iframe ;) : https://bugs.limesurvey.org/view.php?id=14664

But take more time.

And : use jquery ajax too, not own functionnality … real XHR …

@gabrieljenik
The fix proposed break the upload on all browser.
https://forums.limesurvey.org/forum/can-i-do-this-with-limesurvey/121410-upload-turn-blank-with-google-chrome?start=15#201825

Commenting this line make it work again.
// iframe.setAttribute('srcdoc', this._settings.action);

iframe.setAttribute('srcdoc', this._settings.action); == $(iframe).attr('src',this._settings.action) ?

I just followed the gabrieljenik github fix.
https://github.com/LimeSurvey/LimeSurvey/pull/1445
I cannot argue about what this code does.

Hi All,

That was a WIP which still needed testing.
It worked for me and as it was late and urgent, I sent it for testing.

I see that fix wasn't good enough and then suggested rolling back and removing the srcdoc line.
I want to review the prior upload file bug as to see why that line was introduced.

Sure, gabriel. Thanks for help! :)

If you need help with testing, can jump in anytime.

This modification in on my server since yesterday (commenting the srcdoc line).
The upload works again. TX!

If you need help for further testing, let me know.

OK, this could be a possible explanation for what happened:
https://stackoverflow.com/questions/62022757/ajaxfileupload-is-not-woking-in-latest-version-of-chrome-version-83-0-4103-61/62183097#62183097

From my understanding:
0 - LS upload is working
1 - Chrom applied a fix
2 - LS got broken, as well as many platforms using ajax upload mechanisms (I have read Drupla got the hit too).
3 - LS applies a fix.
4 - Chrome rollsback part of the fix or applies a new one (irrelevant).
Now, the code at "3" doesn't work and code status at "0" works
5 - We rollback to "0" status

I tested by going back to Release 3.22.17+200525(Step 0 in above comment), i was able to successfully do the file upload and than i checked out to latest PR(Step 5 in above comment) and tested seems to work fine there as well.
Please refer the attachment for more details.
@criugmls : Can you also check with the latest PR once
Thank You

I tested by going back to Release 3.22.17+200525(Step 0 in above comment), i was able to successfully do the file

Then the issue are added between 22.17 and current ?

Because we add a workaround for a chrome bug ?

Yes, it seems so

@sushmanadendla ,Im sorry but what is "the latest PR"?

Hey @criugmls - please see: https://github.com/LimeSurvey/LimeSurvey/pull/1445 . Gabriel deleted the fix provided some time ago by Patrick. Have time to test it? If everything ok, we will release LTS tomorrow once again.

I commented the line yesterday. No problem since.
// iframe.setAttribute('srcdoc', this._settings.action);

I just deleted it completly today and the upload question is still OK.
Thanks a lot! You are a great team!

You can test it here:
https://limesurvey.criugm.qc.ca/index.php/662578?lang=fr

great, then a new release will come tmrw. Thanks for quick update. (saw too late which lines were commented out, basically those were deleted)

Fix committed to 3.x-LTS branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=30220

Fixed in Release 3.22.23+200626