Open Drupal 8 Webform in Modal

Creating a webform modal is quite simple and straight forward in Drupal 8.

We only need the Webform module and some classes for the modal opening button:

1. Download and install https://www.drupal.org/project/webform
2. Create a webform
3. Check (allow) the webform decicated URL option in the webform settings: /structure/webform/manage/MYFORM/settings:
4. 
5. Optionally change the URL or leave the field empty to use the default (see help icon)
6. Optionally allow parameter prepopulation in fields, if you'd like to provide a parameter via webform URL
7. Add the class "use-ajax" and the data attribute: "data-dialog-type='modal'" to your trigger button:

   Open webform in Modal

8. Add modal styling, if required

That's it! :)

More information (but a bit older): https://www.previousnext.com.au/blog/understanding-drupal-8s-modal-api-…