AMP Conf 2019. April 17/18. Tokyo.

Contributing to WebKit for a more predictable web platform


Over the past two years, the AMP Project has been working with Igalia to identify bugs and missing features within iOS WebKit and then fix them. We create repro cases, write web platform tests, perform debugging and analysis, and, of course, write patches to actually fix things. We think this is particular rewarding work, because it helps ourselves achieve our goals faster, but also makes the web more predictable for developers overall.

In this blog post, we provide an overview of the work done in 2018 with hints about when improvements will be available in iOS releases or when they will have to be handled by Apple. Some of this work is still in progress and we keep proposing new ideas and reporting bugs.

iOS 12.1

We submitted patches for the following bugs which are now fixed in the latest iOS 12.1 releases:

Additionally, Igalia assisted Apple with improvements to custom elements. This one is fixed in the latest iOS 12.1.1 beta:

iOS 11

We have been watching some improvements and verified that they are included in the latest iOS 11 releases. These two items were handled by Igalia in 2017 thanks to support from the AMP project:

  • Improving frame sandboxing, including implementations of new sandbox attribute values such as allow-popup-to-escape-sandbox, allow-top-navigation-without-user-activation and allow-modals flags.
    This allows apps to more securely sandbox ads from doing bad things.
  • Fixing flickering for fixed positioned elements in iframes when touch scrolling is on. See bug 175135

These bugs triaged by us were fixed by other WebKit developers:

WebKit trunk

We have collaborated with Igalia’s and Google’s Web Platform engineers to make the following features available in WebKit trunk. Apple does not comment on future releases but we keep watching them to verify when these improvements arrive in iOS releases.

To be handled by Apple

Apple has been working on two big features that are interesting for AMP:

After analysis and discussions we concluded that it will be up to Apple to fix the following issues:

Work in progress

We are working with Igalia on the following improvements and some patches are already available:


We are thrilled to continue collaboration with Igalia and other browser developers in order to keep improving WebKit’s web platform implementations. Next year, we plan to continue the effort on the current tasks but we also have various other ideas related to networking, UI and more. Stay tuned!

Posted by Frédéric Wang, browser engineer at Igalia