Device: iPhone 6 The demo: - parent document: http://jsbin.com/panoke/edit?html,css,output - iframe document: http://jsbin.com/somuhix/edit?html,css,js,output To reproduce: 1. Open http://output.jsbin.com/panoke/quiet in the portrait mode 2. Switch to landscape mode. Observe the reported resize event with the viewport width 667 (window.innerWidth = 667) 3. Switch back to portrait mode. Observe the reported resize event with the viewport width 667 (window.innerWidth = 667) again, which is incorrect. Expected: When rotating back to portrait mode, the expected viewport width should be 375. The child iframe document sets the width on one of its elements based on the viewport width. This, however, should only affect scrollWidth and not viewport width. Workaround: Instead of `iframe {width: 100%}` CSS, use `iframe {min-width: 100%}` (or even `iframe {min-width: 100%; max-width: 100%}`) - that fixes the problem. It appears that `width: 100%` explicitly triggers some different mode on the iframe.
<rdar://problem/28660040>
Created attachment 300208 [details] testcase
Created attachment 300209 [details] testcase
Testing with the simulator, the bug seems to be fixed on trunk (I can reproduce it with iOS 10.0 though).
Created attachment 334041 [details] Patch
Comment on attachment 334041 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=334041&action=review r+ w/ nits > LayoutTests/fast/events/ios/rotation/resize-iframe-after-orientation-change.html:26 > + uiController.simulateRotation('${orientation}', function() { let use either single or double quote throughout the test. > LayoutTests/fast/events/ios/rotation/resize-iframe-after-orientation-change.html:43 > + await rotateDevice('portrait'); > + var output = document.getElementById("output"); > + var outer = document.getElementById("outer"); > + shouldBe('document.getElementById("frame").scrollWidth', 'outer.scrollWidth'); > + shouldBe('document.getElementById("frame").contentDocument.getElementById("inner").scrollWidth', 'outer.scrollWidth'); ditto, unless where the difference makes sense.
Committed r228692: <https://trac.webkit.org/changeset/228692>