214970 2020-07-30 08:48:14 -0700 [iOS] Calling preventDefault() in a pointerdown event handler for an <img> does not prevent system drag 2020-07-30 08:51:23 -0700 1 1 1 Unclassified WebKit UI Events Safari Technology Preview Unspecified Unspecified NEW https://bugs.webkit.org/show_bug.cgi?id=214968 InRadar P2 Normal --- 1 graouts webkit-unassigned hi webkit-bug-importer wenson_hsieh oldest_to_newest 1676387 0 graouts 2020-07-30 08:48:14 -0700 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. 1676388 1 webkit-bug-importer 2020-07-30 08:48:37 -0700 <rdar://problem/66329423> 1676389 2 405572 graouts 2020-07-30 08:48:50 -0700 Created attachment 405572 Test 1676390 3 graouts 2020-07-30 08:50:11 -0700 This came up while fixing bug 214968. 1676391 4 graouts 2020-07-30 08:51:23 -0700 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. 405572 2020-07-30 08:48:50 -0700 2020-07-30 08:48:50 -0700 Test img-pointerdown-preventdefault.html text/html 289 graouts PGltZyBzcmM9ImRhdGE6aW1hZ2UvcG5nO2Jhc2U2NCxpVkJPUncwS0dnb0FBQUFOU1VoRVVnQUFB R1FBQUFCa0NBUUFBQURhNjEzZkFBQUFhVWxFUVZSNDJ1M1BRUkVBQUFnRG9LMS9hSTNnMzRNR05K TVhLaUlpSWlJaUlpSWlJaUlpSWlJaUlpSWlJaUlpSWlJaUlpSWlJaUlpSWlJaUlpSWlJaUlpSWlJ aUlpSWlJaUlpSWlJaUlpSWlJaUlpSWlJaUlpSWlJaUlpSWlJaUlpSWlJaUlpSWlKeVdYbWZaQUVN cS9LTkFBQUFBRWxGVGtTdVFtQ0MiIG9ucG9pbnRlcmRvd249ImV2ZW50LnByZXZlbnREZWZhdWx0 KCkiPg==