Change the date format for the form display

Not sure how this applies since it is an element, so it should be localized by your browser? Or are you on a browser like Firefox that uses the polyfill?

Yeah, the HTML5 datefield isn't always great, or even user friendly in terms of format. Maybe we should allow selecting the html type ?

@Camster I agree, also want to be able to easily change the format for editing dates as one could in D7.

For example, the Drupal project/module page release dates sensibly use ordering-friendly YYYY-MM-DD, but the edit form for Date in Drupal8 seems to be fixed at dd/mm/yyy using a widget.

These are input type=date elements, which don't have format specifiers per the spec.

I fear allowing users to specify the HTML type for these will get us closer to the do-it-all road.

I am leading towards keeping these the way they are in core, and having this be something the contrib space can handle, since it would just be swapping out the form widgets.

?

would also like to see this! There are so many different reasons why you may need to change the date format within the form.

This is a huge user experience improvement that would be helpful out of the box.

Can the default date format Y/m/d be changed to m/d/Y in the edit form with a hook alter and what hook can be used?

#14, yes and no. The widgets use the Datetime form element, which by default uses the HTML5 input elements. Those require the HTML5 date and time formats (Y-m-d and H:i:s). If you want a different format, you need make a new widget and change the types to text so you can specify your own format (but you lose the popups), or you can do this via a form_alter. Off the top of my head, I am not positive which form_id to target with the form_alter.

In case anyone needs this

function mymodule_element_info_alter(array &$types) {

  // Set defaults for datetime fields.
  $types['datetime']['#process'][] = '_set_datetime_defaults';
}

/**
 * Set defaults for datetime fields.
 */
function _set_datetime_defaults($element) {
  // Add placeholders to all datetime fields.
$element['date']['#attributes']['data-drupal-date-format'] = ['m/d/Y'];
  $element['date']['#date_date_format'] = 'm/d/Y';
  $element['date']['#attributes']['placeholder'] = ["MM-DD-YYY"];
  $element['time']['#attributes']['placeholder'] = ["HH:MM:SS"];
  
  return $element;
}

@leisurman that code works fine for the ui part but date fields have validators that expect the HTML5 format on the backend.

I think we should do something similar to what is explained on this thread
http://stackoverflow.com/questions/27850791/input-type-date-format-and-d...

But I feel it should go into contrib with a new field formatter with its own config.

I don't know how can we have a interface to change the the date format of other widgets like the published date but that can probably can be handled in the contrib module.

Here's a nice example of things simply not working. Using Drupal 8.4.x. and the core media module, I've added a standard "Date" field to a media entity. In Chrome, the field expects the input to be mm/dd/yyyy, which makes sense in my part of the world.

The field itself expects YYYY-MM-DD, which I wouldn't mind either. However, neither of these are configurable that I can see, resulting in an error.

Never mind, the date format wasn't the problem in my case, I needed to enter a time. It submitted fine in the specified format. I'd like to make the time optional but that's another issue.

See also: #2791693: Remove sample date from date field error message and title attribute

#16 worked for me but then the form validation wont accept this format for InternetExplorer.
It does validate for other browsers tho...
Weird, isnt it?

#16 is no more working on D8.9.1
As an example for why this is not working, the key $element['date']['#attributes']['data-drupal-date-format'] used in the #16 code doesn't exists anymore.
I changed the priority into Major, because There is no way to change the format of the date widget.
Use case: European peoples working on English system/browser (which is very common) => they need a d/m/Y widget.
The only way I could solve this issue is to use the select list plugin

I am running into a similar problem.

I have a use case where the user needs to be able to copy the date from another source and paste that value into the date field. It would be too time-consuming to have to pick the date from a "date picker" widget. It would be ok if it were a one-off situation but this user needs to be able to enter several at a time.

I agree that it would be extreemly helpful if a "Text Field" Widget was available again.

Discovered this while looking for duplicates, tagging Bug Smash Initiative.

There is a later issue, with more discussion and patch, for this problem. Although this is the earliest I have found closing this as a duplicate.

Hi all,
Just to comment on the workaround I have used to solve this, in case it helps someone.

Contrib module: Datetime Flatpickr (https://www.drupal.org/project/datetime_flatpickr)
Configuration for the Flatpickr datetime picker:
Alternative input format: d/m/Y
Date format: Y-m-d

Regards,