Introducing the IE9 on Windows Phone “Mango” User Agent String

Introducing the IE9 on Windows Phone “Mango” User Agent String

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With Windows Phone “Mango” declaring RTM and developer tools hitting “RC”, it is time to start getting websites updated for Internet Explorer 9 (IE9) availability on Windows Phone. In today’s post, we’ll describe changes to the browser’s user-agent (UA) string so that you can start testing those website updates.

Changes to the UA string for IE9 on Mango

The updates to the Mango UA string mirror changes made to the IE9 UA string on Windows. In fact, we can reuse most of the description from the original post announcing the IE9 UA string on Windows (the only difference is the version numbers we are moving from):

  1. Application version is incremented from ‘Mozilla/4.0’ to ‘Mozilla/5.0’ to match other browsers (explained well in the great History of the user-agent string post). This change signals that IE9 is an interoperable browser.
  2. Version token is incremented from ‘MSIE 7.0’ to ‘MSIE 9.0’.
  3. Trident token is incremented from ‘Trident/3.1’ to ‘Trident/5.0’.

In addition, we have incremented the mobile-specific version from ‘IEMobile/7.0’ to ‘IEMobile/9.0’ and updated the OS version as well. Note that IE on Windows Phone has always sent the “short” UA string – pre and post platform registry value tokens are not supported.

With these changes, the default UA string for IE9 on Mango is:

Mozilla/5.0 (compatible; MSIE 9.0; Windows Phone OS 7.5; Trident/5.0; IEMobile/9.0; <manufacturer>; <model> [;<operator])

The manufacturer and model information is populated automatically into the end of the UA string. The mobile operator also has the option to add their name to the end, so you may see that token at the end of the UA string on some Mango devices.


IE9 on Mango supports compatible document modes similar to IE9 on Windows, controlled via a compatibility list. If a site is set to IE7 or quirks document mode on that list, the UA string that is sent will be:

Mozilla/4.0 (compatible; MSIE 7.0; Windows Phone OS 7.5; Trident/3.1; IEMobile/7.0; <manufacturer>; <model> [;<operator])

We’ll describe more details on how the compatibility view list works on Mango in a future blog post.

Finally, note that for app compatibility reasons, apps that use the WebBrowser control will send the old Windows Phone 7 (IE7) UA string until they are re-compiled with the WPSDK 7.1.

Best practices

While the UA string is an important means of identifying a browser, you should not rely on it to target specific functionality. Instead, use feature and behavior detection to detect specific browsers wherever possible.

If you do decide to use UA detection, we suggest using the “IEMobile” token to identify Internet Explorer on Windows Phone as a mobile browser. If you would like to target modern markup at IE9 (and future versions of IE) on Windows Phone, you use a regular expression to extract the IEMobile version token then check if it is greater than or equal to 9.0.

Call to action

  • If you are already detecting Windows Phones on your site using UA string detection, make sure that your detection logic continues to work correctly with the IE9 UA string. Based on our internal testing, there are several sites that detect the WP7 UA string but not the Mango UA string.
  • If you have a tiered experience based on browser capabilities, now is a great time to start enabling richer functionality (e.g. HTML5 video) for IE9 on Mango devices. If you are using feature detection, some of this should happen automatically but be sure to grab the emulator or upgrade your developer devices to double-check. Look for deeper dives on new functionality enabled in IE9 in Mango in upcoming blog posts or let us know in the comments if there are specific topics you’d like to see covered!

Charles Morris
Program Manager Lead, Windows Phone

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  • bpa
    3 Posts

    I just bought a Focus S and I love it, but I can't figure out how to move forward through IE history.  Back is obvious, but forward seems to be missing.  Also, hoe can I find a word on a page?

  • I don’t see any recent dofollow links. Are you still posting these?

  • Thanks. I will bookmark this page and use it.very help full blog.

  • andycted
    43 Posts


    glad to hear it. I have to admit I was a bit disappointed by the slow performance on JS and some compliance with some websites... the html5 part is very cool, but would I be wrong in assuming that you had to partially rebuild the engine from scratch and that you still have wide margins of improving it ... ?

  • You'll have to forgive my ignorance here, but will the UA string for WP7 devices always change with each new version of the device software, or is Mango such a large improvement that in this particular case it was a warranted change?

    My concern is that if someone is using the UA to identify the device manufacturer and model they might encounter issues once the UA changes for a device that was already able to be properly identified.  I know there's a difference between loose matching and exact matching of the UA, I'm just not 100% positive the same previously exact matched device would be correctly loose matched given the new UA string.

    Thanks for your time.

  • Thanks for the acknowledgement @Charles Morris. The multi-tasker for tabs can be handy sometimes, but as you know the list of available tabs changes quickly when you're using the phone. Regardless, I'm just glad to know that at least you're monitoring the user voice forum. I've posted some ideas there including the two I've already mentioned that have gathered some support, but at one point stopped since I felt it pointless with no response from MS. That said, I'd be happy to work with you guys to provide further feedback if needed :)

  • Rick Xu
    2 Posts

    @Tom Warren – You can fix that by using the latest way of embedding YT video by using an <iframe> tag, which gives us HTML5 video instead of Flash: The Mango browser provides support for legacy Flash-based YT video using <embed> but there are some limitations.

  • @andycted - Look for an upcoming post that covers an overview of what IE9 on Mango brings from a developer perspective.  HTML5 is a big part of the story but by no means all of it. :)

  • Tom Warren
    132 Posts

    @Rick Xu - If you visit on your WP7 device it will load a mobile theme. The theme should shrink YouTube videos to a smaller width and height. It works correctly on iPhone and Android but not WP7 Mango.

  • andycted
    43 Posts

    @Charles Morris

    is the main focus of ie9 on html5 ? (I'm repeating my question in the event you 'missed' it) or are you going to try and optimize rendering and js as well

  • @schnoz - Thanks for the feedback.

    We're aware of the feedback around the Mango design (and monitor a number of feedback channels) - keep it coming!  Look out for a future blog post detailing our design goals in Mango.  In the meantime, remember that you can now use the multi-tasker (press and hold back) to swtich between recently used tabs.

  • schnoz
    1 Posts

    Well, it's at least good to finally have someone from MS acknowledge the "Find on Page" issue. I had posted about it on uservoice (, but couldn't get a pulse from MS. @Charles Morris, any word on changing the address bar as per this: I've been using Mango betas since they were available and I can tell you this is one of the most frustrating, non-intuitive, and non user-friendly issue I've faced on the new OS yet. And as you can see by the number of votes, I'm not the only one feeling that way. Also, @Charles Morris, is the uservoice forum officially monitored by MS?

    Thanks and keep up the good work.

  • @BliTz7 The date is dependent on when the OEMs finish their part of the update (drivers, etc.) Only then will Microsoft begin scheduling the update and as of now MS itself might not know when exactly they will be able to begin the rollout. So wether or not "rumor" is convincing or not it simply means: might happen, might not.

    As for the new UI. It definitely reflects many wishes the community provided over the last year (e.g. address bar in landscape). Perhaps we will see some of the functionality return when the next small update arrives (Tango?) which should not take that long but you're right in that it might take until the next major update.

  • BliTz7
    6 Posts

    Good news !

    Off-Topic : I have one question... MANGO will release 1 September or it's wrong ?

    Because "Just a rumor" isn't convincing ^^

  • I really hope forward and backward buttons. It's really annoying when you leave IE and then wants to go back in the page.

  • andycted
    43 Posts

    Removing the 'find on page' really wasn't a good move and if history teaches something 'in the future' means in a year or so...

    I had high hopes for ie9, but it seems to me you mostly only added and optimized html5, while bringing the interface a couple of steps back. Also, there were a few websites which showed perfectly on NoDo, but are impossible to see in ie9 and some Javascript intensive ones are still extremely slow...

    My question is: is this planned, like you rebuilt the browser from scratch and need to improve it, or is ie9 only focusing on HTML5 ?

  • KR
    503 Posts

    Please can someone tell me if IE9 in mango will still have the phone's search button sending you to the Yahoo search page(which is depressing and the results are dumb),i'll like a way to assign it to Google search(like it or not its the best search engine)

    Coz right now bing gives me dumb results(I guess because i'm not in the USA)

    So my search button is currently useless(if only I could assign it to the Google search app!)

  • KR
    503 Posts

    Reason for requesting the app is that I browse this blog frequently from my HD7,in which IE mobile cuts some letters from each line on the comments,so I always have to read the entire comment before getting the true sense

  • KR
    503 Posts

    Can we get an app for this blog?or i'm I asking too much?

  • fm1381
    1 Posts

    When will html5 Bing Mobile display properly on IE9 for WP7? It doesnt display anything like it does on Android or iOS. It basically shows 4 categories on the bottom left and you can't even click "Explore" option to see more.

  • @jstawski @Krush

    That isn't really the issue here. Marketing team can use Windows Phone 7.5 as a brand/product name, and Developer team uses Windows Phone "OS" 7.1 for software versioning.

    I think the real issue is that the UA describes its operating system as "Windows Phone OS 7.5".

    What's "Windows Phone OS 7.5" ? WTF.

    It will cause significant branding disruption.

  • qsr786
    3 Posts

    hmm I thought that with mango I would have 50 fps as they showed in the wpc last month..

  • abm
    268 Posts

    @Charles Morris, someone said you guys have removed the Find on Page feature from IE9-Mango? Can you please confirm this? For me , it is THE most lovely feature of IEWp7... Even the ape-phone is not providing this at the moment. There is no point in removing this tiny valued feature. Please bring it back if it’s true :(

  • Please create view for SmartPhone of this blog, just I want to read this blog on IE9 Mango, iPhone, Android, and share these great contents with our friends.

  • @qsr786 - Don't expect big performances changes between Beta2 and RTM from the software side.  I can't comment on driver updates that will be packaged with Mango since that is controlled by the device manufacturer.

    @frankwick - Find on page is not available in Mango.  We know it is useful in some scenarios and plan to bring it back in the future.

  • @Krush You, I was trying to be funny to make a very serious point that Microsoft should start to take care of. I completely agree that Mango should be a semi major release and be versioned as 7.5, what I don't agree is why does the dev division need to label it as 7.1. This generates confusion even within the "nerd" community. Developers then start bloging about 7.1 and search engines start to pick it up and the next thing you know is reviewers/consumers start calling it 7.1 and others 7.5. Then the end user doesn't even know the difference between 7.1 or 7.5, they will check their system settings to see they are running 7.1 and look all over to get their 7.5 update. It just too confusing and very bad for user experience. Not to mention developers that will want to start coding for WP 7.5 and won't find the 7.5 SDK, they will find the "older" 7.1 SDK.

    To top it off, which made me write this post, is that the User Agent, which is a "nerd" thing, meant to be used by developers, shows as 7.5, instead of 7.1.

    This has to stop, just bring the build up to par with the marketing version, how hard can it be?

  • frankwick
    37 Posts

    Speaking of IE9 in Mango, where i sthe "find on page" option.  It was there in IE8/NoDo.

  • qsr786
    3 Posts

    txh for the quick answer Iam running mango beta 2 on hd7 and get around 30 fps in the mobile version fish test, will there be a speed improvement in the final RTM mango version cause some people say that the hardware manufacturers will include new  drivers for it is it TRUE?

  • @qsr786 - We can't guarantee a specific framerate due to hardware variance, but we do expect to see a smooth framerate on all WP7 devices upgraded to Mango.  Be sure to use the mobile-optimized version of the demo here:

  • Rick Xu
    2 Posts

    @Tom - Thanks for your comment. Could you let me know the specific website you tested on that reproduces the bug? I did a quick test by altering the width attribute of the embed/iframe tags for YT videos and the browser behaves fine.

  • qsr786
    3 Posts

    Hey I have a question hope someone can help me will the ie9 in mango in my hd7 device will get 50 fps in the fish tank test, in the ie test site?

  • Krush You
    94 Posts

    @jstawski- MS has always worked this way... Windows 7 is actually 6.1 - the Codebase is 7.1- consumers will not care about this only nerds are going to care about this. For consumers its listed as 7.5 because its a pretty big jump when it comes to features and new updates and additions.

  • @jstawski Now that's just good humor :-)

  • I can picture the meeting between the dev division and marketing division:

    Marketing: "we need to make sure that everyone knows that Mango is a huge improvement from WP7. We need to call it WP7.5"

    Devs: "Yes, but we can't just jump from 7.0 to 7.5, it needs to be 7.1"

    Marketing: "Listen, you nerd, if it wasn't for us you wouldn't be sitting here, just label it 7.5"

    Devs: "You know what, you suck anyway, your ads are stupid and haven't sold a single phone, we're just labeling it 7.1"

    Marketing: "Fine, we'll just stick to the Microsoft way of doing things and confuse everyone. We go with 7.5 and you go with 7.1"

    Devs: "Ok, then to make it even more confusing, we'll add 7.5 to the user agent, instead of 7.1"

    All together: [Evil Laugh]

  • Tom Warren
    132 Posts

    It's a shame the YouTube embed width bug was missed in Mango RTM. In build 7720 if you have a YouTube video embedded in a mobile site, Mango IE9 does not read the width settings for the embed. Webkit browsers like Android and iOS work fine.