Created attachment 338799 [details] Iframe Zoom Click Repro The attached file has an anchor labelled "Click Me" containing an onclick attribute of "alert('Clicked');", as well as an iframe sourced to a youtube video. Repro: 1. Focus the video in the iframe 2. Zoom In 3. Zoom Out 4. Click "Click Me" on the parent page Expectation: "alert('Clicked');" is executed and an alert box displays Observed: The click event only seems to dispatch (and the alert box display) a fraction of the time. Anecdotally, although the link should be at position 0,0 during all of the steps above, document.elementFromPoint(0, 0).click() also fails to result in a dispatched click event to the anchor element during the zoom operation as well.
What do you mean by "focus the video"? Should I tap the play button to start it playing?
Does the bug occur if the "Click me" is not inside position:fixed?
<rdar://problem/40569615>
Can you put a "click me" outside the position:fixed for testing, and move it away from the edge of the page so that it's easier to test? Does the size of the hit target make any difference?
I have shown the repro in a video here: https://www.youtube.com/watch?v=mqf8vJiu-yY - in the video I have taken the link out of the position: fixed container as well and it persists.
has there been any progress on this issue? It would really mean a lot. Thanks much.
A temporary workaround we've found is adding a touchstart event handler to the body. After that, the click events work properly and all is good again.
Created attachment 343530 [details] Simpler repro, removes unnecessary CSS; still matches the youtube video sent in an earlier comment
Created attachment 343531 [details] Workaround -- an empty "ontouchstart" attribute allows for the separate click event to be dispatched. The reported issue can not be reproduced using this attachment.
Mass move bugs into the DOM component.
This is a major issue as my website consists of a feed of embedded youtube videos. UI is rendered useless on iOS. Adding ontouchstart="" to the body works in the beginning, but as the user keeps scrolling the issue presents itself again.
I can reproduce.
The issue is that if you happen to put a finger in the YouTube iframe when zooming, WebPage::updatePotentialTapSecurityOrigin() puts youtube.com's security origin in WebPage::m_potentialTapSecurityOrigin and it doesn't get cleared, causing later potential taps in the main frame to fail.
We assume that any time a touch event is a potential tap, our single tap gesture recognizer will identify the potential tap (even if it never commits). That's a false assumption. In this case, the first touch event in the pinch gesture is a potential tap, but the second touch event occurs before the single tap gesture recognizer identifies a potential tap.
That false assumption causes this bug because we set m_potentialTapSecurityOrigin when a touch event is a potential tap, but never clear it until a potential tap in the WebPage sense either commits or cancels. I think we can fix this by clearing m_potentialTapSecurityOrigin each time we see a new touch start event.
Created attachment 371254 [details] Needs a test
Created attachment 373454 [details] Patch
Created attachment 373455 [details] Fix open source build
Comment on attachment 373455 [details] Fix open source build Thanks for the review!
Comment on attachment 373455 [details] Fix open source build Clearing flags on attachment: 373455 Committed r247161: <https://trac.webkit.org/changeset/247161>
All reviewed patches have been landed. Closing bug.