CSS Zoom support for mobile WebView

Not reproducible Issue #10946333


Chris M.
Feb 13, 2017
This issue is public.
Found in build #
Reported by 1 person

Sign in to watch or report this issue.

Steps to reproduce

  • CSS zoom factor works properly on in Edge on my desktop/phone and also in a WebView on my desktop, but on my phone the zoom factor does nothing in a WebView. This is the RS1 build of Windows Mobile in the Release Preview insiders channel on mobile.

  • I tested in a WebView both with my own code as well as with this page: https://css-tricks.com/almanac/properties/z/zoom/

I’m unsure if it’s just disabled in WebView Mobile, if it’s already been fixed and it’s the version I’m using or what. I thought it might be something I have to implement myself, but that can’t be the case since it works in a desktop WebView. I need this style to work reliably across desktop/mobile in a WebView.

Does the feature get disabled on mobile if the device’s display settings have the content scaling set to something other than the default?

To be explicit, CSS transform: scale() works, but that is more like a zoom gesture rather than zoom factor which scales the content itself instead of the rendered view. It seems to tap into the same function Edge uses for its built in Zoom option (ctrl+scrollwheel).



0 attachments

    Comments and activity

    • Microsoft Edge Team

      Changed Assigned To to “Brad E.”

      Changed Assigned To from “Brad E.” to “Steven K.”

      Changed Steps to Reproduce

    • Hi Chris,

      Apologize for the delay.  Have you tested this in a recent Edge mobile version?  Thought I would check because there have been a lot of changes since this was posted.



    • Hi Steve,

      I need to update my phone to the latest build, though it’s my daily driver and not on the supported devices list so I need to do it on a day where some downtime won’t be a big deal. Will try to do it soon and report back. Thanks!

    • My apologies, updating to an insider build “bricked” my HTC One M8 (which was bound to happen eventually) and WDRT can’t save it, so it may be a while before I can get around to testing this. I’m stuck with Verizon for various reasons which isn’t very Windows Mobile friendly and will likely just not have a phone for a while since I refuse to use an iOS or Android phone. :P Not that big of a deal, though it makes testing this tricky. Current plan is to wait for the battery to drain then cross my fingers (all forms of reset are unresponsive, but I see it listed in the router table, so it’s on) and see if it will boot after that.

      However, if someone else would like to test it they should be able to pretty quickly.

      • Create a basic UWP app in Visual Studio and drag a WebView control into it and then have it go to https://css-tricks.com/almanac/properties/z/zoom/

      • Compare the results in the WebView on mobile with the results in Edge on mobile (it always worked in Edge, just not the WebView)


    • Chris,

      Thank you for the response, and sorry to hear about the bricked phone.  Did the phone by chance update to the unintentional insider release from JUNE 1, 2017?  If so, take a look at the following information.


      The recovery tool might help either way?


    • Also, this might not work if you did not have RDP enabled on the phone but worth a shot.


      USB or Bluetooth would have had to be enabled before hand as well.  :/

    • Thanks for the suggestions, Steve. I was aware of the unintentional build that went out, but from my understanding that was resolved by the time I did an update.

      I also had thoroughly looked over the WDRT FAQ before using it at all and had no luck with it. Every method I saw with WDRT required me to have the ability to reboot the device, which is something I do not have the ability to do. If I could just pull the battery out of the phone that would be great… but that’s not how a lot of smartphones are made these days. :/ I figure it reduces calls to support and makes it easier to moisture-proof it.

      Pretty sure I had remote access disabled, but I wasn’t aware you could RDP via USB outside of the functionality the Project My Screen feature provided. That also seems like a no-go at the moment, though and since the update attempt the phone device doesn’t show up when plugged in. It would make the USB connection noise once, but then nothing.

      I had been watching on my Microsoft account devices page and the phone hadn’t sent an update there since some time on the 8th. It was still listed as connected to the router and responding to pings earlier today, but it has since fallen off and the LED on the phone was blinking for low battery. I just tried plugging in the USB cable to see if I could maybe give it power and get it to boot up. It was still unresponsive, however this time I heard the Windows device connect/disconnect noise cycled 6-7 times and then stopped so I don’t know if the phone was boot cycling or what, but that was unusual.

      The blinking LED has stopped now, which could be very bad or it could just be that the USB being plugged in for 30 seconds managed to give it enough charge to be above the battery warning threshold. If it starts blinking again tomorrow, I’ll probably continue the plan to just let it run out and see what a fresh boot does.

    • Okiedoke, the battery ran down and I was able to boot it up, though only with it plugged into the wall (it needed more power than PC USB power was providing). Immediately got an e-mail from the Microsoft Devices Team saying my phone was found. :P

      The version that got installed was 10.0.15063.251 (creator’s update) from the release preview channel and there was another pending update for 10.0.15063.297. Not sure what build CSS zoom fixes would’ve made it into, so I figured I may as well update to the latest one available in this channel. 10.0.15063.297 is installed now and I’m going to let the phone chill for today so hopefully it can do any post-update stuff it wants undisturbed.

      Assuming it’s still fine by tonight, I’ll try to push a CSS zoom test to it and report back.

    • Alright, both good and bad news.

      I’ve tested on both 10.0.15063.297 and 10.0.15063.414 now. The zoom style does work when tested on that page up above in my WebView in these updates.

      It also works on most other pages. However, I’ve run across a number of pages where you can use zoom to scale up on the desktop WebView just fine, but on the mobile the results are a bit spotty. What I mean is that in the desktop WebView you can do a simple 200% increase and it works exactly as you’d expect without any fuss on any page. On mobile, some pages will do nothing at 600% or even 1100% and then suddenly start scaling at 1400%. Meanwhile the desktop WebView on those same page doesn’t require such excessive values.

      I would think that maybe it would be related to mobile display scale settings, except that it works fine on many pages. I’ve been fiddling with it for a while and it seems possible to get the results I’m after with a bunch of workarounds, but I’m worried that will be fragile.

    • Microsoft Edge Team

      Changed Assigned To from “Steven K.” to “James M.”

      Changed Assigned To to “wwatri”

      Changed Status to “Not reproducible”

    • Hello,

      Thank you for providing this information about the issue. Unfortunately, we are unable to reproduce this problem in Edge with the information at hand. Please reopen this case when you can provide consistent repro steps or new information for us to consider.

      Best Wishes,
      The MS Edge Team

    You need to sign in to your Microsoft account to add a comment.

    Sign in