Since Firefox 52, DragEvent.dataTransfer becomes null when in debugger.

[Iziminza]

MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/DragEvent

What specific section or headline is this issue about?

Instance properties, dataTransfer

What information was incorrect, unhelpful, or incomplete?

Since Firefox 52, this property becomes null when in debugger. This should be documented, since the fact that you are debugging should not normally change code behaviour!

What did you expect to see?

Text like "Note that this property may be set to null when debugging in Firefox."

Do you have any supporting links, references, or citations?

Yes: https://stackoverflow.com/questions/43180248/firefox-ondrop-event-datatransfer-is-null-after-update-to-version-52

Do you have anything more you want to share?

No response

MDN metadata

Page report details

• Folder: en-us/web/api/dragevent
• MDN URL: https://developer.mozilla.org/en-US/docs/Web/API/DragEvent
• GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/api/dragevent/index.md
• Last commit: f45409b
• Document last modified: 2023-02-20T07:35:10.000Z

[Josh-Cena]

Thanks for the information. We'll track this in #11670