Intersection Observer not behaving as expected on Windows Insiders Preview build 14986

Fixed Issue #11299415


Ishaan N.
Mar 16, 2017
This issue is public.
Found in
  • Microsoft Edge
Fixed in build #
Reported by 1 person

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Steps to reproduce

Intersection observer has some inconsistencies that our team detected. We built a test page that uses Intersection observer to log the percentage of the red square viewable. At certain instances, even though 100% of the square is visible, it would log only 92% of it is visible. Upon zooming in and zooming out there are even more inconsistencies. When zooming out to 25%, the browser logs 0% of the square is in view, even though 100% of it is. Similarly, when zooming in, the browser logs that 99%-100% of the square is in view even though far less of it is in view. We double checked and none of these inconsistencies exist on chrome or on firefox’s version of a preview build.


Comments and activity

  • Microsoft Edge Team

    Changed Assigned To to “Steven K.”

  • Hi, I saw that the latest Windows 10 Creators update was released (build 1703) and Intersection Observer was formally released on it, with a blog post released by Microsoft on the same. I downloaded and did the same tests for Intersection Observer and found that the issues still exist. Would it be possible to get an update on this issue or a timeline on when it might get fixed by? Thanks.

  • Hi Ishaan,

    Would you be willing to provide your intersection_test.html or another repro?  A repro reduces the chance of us not seeing the same issue and reduces the time to triage.

    Appreciate the support,

    The MS Edge Team

  • Hi Steven,

    Sure, the test page I used was:

    It basically uses IntersectionObserver to log what percentage of the red square is viewable (you might have to scroll down a bit to find it initially) on all events such as scrolling, zooming etc. Let me know if you need anything else. Thanks!

  • Hi Ishaan,

    Thank you for the repro.  That helped.  I was able to repro this in the latest internal and insider fast builds.

    Appreciate the quick response and the support,

    The MS Edge Team

  • Microsoft Edge Team

    Changed Assigned To to “Balaji B.”

  • Hi Steven K., just wanted to follow up here. Will this be resolved in the next Edge release?

  • Microsoft Edge Team

    Changed Assigned To to “Christian F.”

    Changed Assigned To from “Christian F.” to “Andrew B.”

    Changed Status to “Confirmed”

    Changed Status from “Confirmed” to “Fixed”

  • Hello,

    Thank you for providing this information about the issue. We are pleased to report this feature is fixed in Edge and will be available in an upcoming Insider Preview build.

    Best Wishes,
    The MS Edge Team

  • Hi,

    Is there a timeline on when this is expected to be flighted?


  • Additionally, is the fix now available in any of the insider previews released since this issue was closed?

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