Use JavaScript to prevent double submission of admin forms

[Manuel Saelices]

For fast clickers.

[Manuel Saelices]

Fixed on this Pull Request: ​https://github.com/django/django/pull/9425

[Aymeric Augustin]

I think this is an improvement and the implementation looks reasonable.

[Tim Graham]

I found an article titled ​JavaScript: Preventing Double Form Submission which might be worth reviewing. In particular, it points out "Rather than simply disabling the button, we can also change the text so that people don't get confused."

Did you consider trying to add some tests for the patch?

I share Nick's concern on the pull request that this may have a good chance of causing some regression in unconsidered edge cases. I'm not sure if it's considered a best practice these days. The article suggests that some browsers (e.g. IE11) treat a double click as a single click. It seems unfortunate if every project has to add something like this.

[Karan Bedi]

I have created a PR. Please guide me how to proceeding further.
​PR

[Carlton Gibson]

Hi Karan,

Thanks for the input. Your fix includes the changes Nick suggested from the original PR. (Great.)

To get this merged we need to address Tim's concerns.

• Can we add some selenium tests, to exercise the behaviour?
• What's your assessment of the article Tim linked to? Do we need (still) to do this?

[Karan Bedi]

Hi Carlton,

• I am unable to reproduce the behavior, probably because till now, I am serving on localhost.
• In the article, there are different methods of implementing the same. One improvement can be changing the label of the submit button after a click.
• From the point of usability, there is just a comment by someone, which also doesn't seem concrete.

Please guide me on how to proceed further.

[Marcelo Galigniana]

For this issue there are currently 2 approaches:

• ​Trigger an alert when submitting twice

• ​Disable buttons while submitting

[Marcelo Galigniana]

I think thibaudcolas's comment in 1st approach makes sense: ​https://github.com/django/django/pull/15217#issuecomment-1018935149

So I updated the PR to go for the first option

[Carlton Gibson <carlton@…>]

In fe7dbef:

Fixed #28889 -- Prevented double submission of admin forms.

Added a JavaScript confirm() to catch double-submissions, when the
change form has already been submitted.

Thanks to Adam Johnson, Claude Paroz, Keryn Knight, and Thibaud Colas
for review.