Added info that not all browsers do submit a button when user submits…

[ThomasLandauer]

… by pressing Enter

This fact has been filed as a (bogus) bug: symfony/symfony#10611

[javiereguiluz]

@ThomasLandauer thanks for this! I'd love to have a concrete list of browsers that don't behave as expected ... but I guess it's difficult to gather the list and maintain it updated.

[ThomasLandauer]

@javiereguiluz: Yeah, sure! But I don't know a list either ;-)

[robfrawley]

We should really point out the browser(s) that are affected by this behavior. The note isn't particularly useful without this context. Further, if we don't know what browsers perform in this unexpected manner, then what is the empirical evidence this occurs at all, right? :-)

[ThomasLandauer]

I did some testing with the browsers I have at hand:
Submit-Button included in submitted form-data:
IE 5: no
IE 7: no
IE 8: no

Firefox 54: yes
Chrome 59: yes
Edge: yes
IE 11: yes
IE 10: yes
IE 9: yes

But I'm hesitant to enter the info that IE 8- is affected, since this might give the impression that only IE 8- is affected - which I just don't know.

Anyway, I think that giving a (debatably incomplete) information that problems might occur is still better than not mentioning it at all!

[robfrawley]

Is it worth mentioning something that doesn't affect any actively supported browsers? All the ones that behave incorrectly are EOL. Just a thought, not necessarily against voting against this change, just wanted to bring up the point. That said, your points are valid as well.

[ThomasLandauer]

Well, as I said, I don't know if other (mobile?) browsers or robots are affected too. The only thing I know is that I did stumble over this issue somehow - otherwise I wouldn't have filed it. But now, 2.5 months later, I can't remember any details...

Other scenario: If you have a GET-form, and there are some links out there, linking to some of your search results, and then you transfer your app to Symfony, those links might break.

So my gut feeling says: In uncertain situations it's better to have some warning than not.

[HeahDude]

Hmm, reading this note I understand that in all my apps I should take care the the user agent header before performing the check...

Not sure we should care.

[javiereguiluz]

Given that this only affects to Internet Explorer 8 and earlier, I prefer to not add this warning in the docs.

However, for those unfortunate people who must deal with this error, let's add some SEO-friendly phrases so they can find this issue when googling about this:

• Symfony Forms error: when submitting a form using the enter button, isClicked() returns true
• Why does the isClicked() method return true in Symfony when I submit a form pressing the Enter key
• Symfony Forms return true for isClicked() when no button is pressed