NEW 214970
[iOS] Calling preventDefault() in a pointerdown event handler for an <img> does not prevent system drag 
https://bugs.webkit.org/show_bug.cgi?id=214970
Summary [iOS] Calling preventDefault() in a pointerdown event handler for an <img> do...
Antoine Quint
Reported 2020-07-30 08:48:14 PDT
Consider this simple markup: <img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAGQAAABkCAQAAADa613fAAAAaUlEQVR42u3PQREAAAgDoK1/aI3g34MGNJMXKiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiJyWXmfZAEMq/KNAAAAAElFTkSuQmCC" onpointerdown="event.preventDefault()"> On macOS, the fact that `event.preventDefault()` is called while handling the `pointerdown` event makes it so that the image cannot be dragged. On iOS the image is draggable after a long press, but I think it should not be to match both the macOS behavior and developer expectation.
Attachments
Test (289 bytes, text/html)
2020-07-30 08:48 PDT, Antoine Quint 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Radar WebKit Bug Importer
Comment 1 2020-07-30 08:48:37 PDT
<rdar://problem/66329423>
Antoine Quint
Comment 2 2020-07-30 08:48:50 PDT
Created attachment 405572 [details] Test
Antoine Quint
Comment 3 2020-07-30 08:50:11 PDT
This came up while fixing bug 214968.
Antoine Quint
Comment 4 2020-07-30 08:51:23 PDT
Useful information from Wenson: the UI process (UIDragInteraction) mediates when to begin a drag on iOS, we’d probably just need to prod it when default is prevented for pointerdown.
Note You need to log in before you can comment on or make changes to this bug.