Email FAPI element was added without support of multiple attribute. See https://www.drupal.org/project/drupal/issues/1174620#comment-4564144 → .
Currently even if the attribute set directly through #attributes property Drupal does not accept comma-separated emails.
$form['email'] = [
'#type' => 'email',
'#title' => $this>t('Email'),
];
'#attributes' => ['multiple' => '']
The email address <em>foo@example.com,bar@example.com</em> is not valid. Use the format user@example.com.
Support "multiple" attribute same way as for select lists.
$form['emails'] = [
'#type' => 'email',
'#title' => $this->t('Emails'),
'#multiple' => TRUE,
'#description' => $this->t('Comma-separated email addresses.')
];
Later, it will be possible to add this option to Email fields as well, but first, an element itself needs to comply with the HTML documentation.
Review
Commit
NA
The API of the Email Render element must be updated.
https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Render%21...
NA
Provide multiple attribute support for Email render element.
Closed: duplicate
10.2 ✨
What is this issue? It looks the same as 📌 Support multiple attribute for email element RTBC .