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May 2, 2012
Windows Phone Developer Blog

Delivering Rich Mobile Web Experiences in Windows Phone 7.5 ( Case Study)

The Windows Phone Browser team has a goal of delivering the best web browsing experience on a smartphone. This goal has many components within our team: from the UI of the browser, compatibility with a wide array of website layouts, and of course buttery-smooth rendering performance. However, even if we execute flawlessly on our end, we are missing a crucial piece – delivering a great web experience is fundamentally a partnership between our team and web developers. Achieving this goal means working together to ensure that your content and services are delightful for users to consume on Windows Phone.

We understand that web development resources are always limited as you keep up with the increasing traffic from mobile devices, and the elusive “write once, run everywhere” promise of web development has not perfectly materialized. However, with IE9 for Windows Phone 7.5, we took a big step in the direction of this promise. By sharing a codebase with IE9 for the PC, we achieved identical support for new web standards and pushed the envelope on real-world performance with industry-leading hardware acceleration. We wanted to hear about developing for IE9 on WP7.5 from web developers directly, so we decided to collect some feedback and share it on the blog. recently deployed their premium web experience to Windows Phone, and we thought it would be great to hear what they had to say about developing for IE9 on Windows Phone. As a side note, ESPN started looking into supporting Windows Phone because of a simple request I made on their support page. Lots of folks on my team are sports fans and were asking me about the site’s experience on WP7.5, so I just dropped ESPN a note like any user would. The message was quickly routed to the mobile site team; I have immense respect for ESPN’s responsiveness and the system they have place to address user feedback. Here’s what Mike Marrone, technical lead, had to say about developing for IE9 on WP7.5:

Overall, it was an easy process. We support only WP7.5 and IE9 thanks to its very good CSS3/HTML5 support. We are in a convenient position of having an existing legacy mobile site that older devices can fallback to. Honestly, development for WP7.5 boiled down to a fairly basic process – IE9 on the PC, being nearly the same browser, was a great dev tool to get most of the way there before final QA on actual devices.

Some other more specific development notes:

  • The “display: box” CSS style is not supported on WP7.5. We use this in carousel experiences to transition elements left or right 100% of the viewport without having to programmatically determine the viewport size (which means the browser automatically updates the positioning upon device rotation, etc.). On WP7.5, we actually used a better alternative thanks to it being the only browser that currently supports the CSS “vw” unit (VERY useful).
    [Amin] See here and here for more information on vw units.
  • The bulk of our CSS differences between WP7.5 and other supported devices was with gradients. WP7.5 has an easy fallback with filters so it was not a big development issue.
    [Amin] See here for information on using Gradient Filters in IE9.
  • JavaScript touch events would be a nice addition.
    [Amin] We hear you, stay tuned!

We look forward to your continued great progress in mobile.

As you can imagine, this was music to our ears! We often use IE on the PC to investigate bugs, and it was great to hear that the tools work well for web development outside of our offices too. We appreciate the feedback (it will inform our plans for future releases) and welcome additional feedback through the comments below.

IE9 on Windows Phone is set up to support rich web experiences with great performance, and often all it takes is updating user-agent logic and using standards based (as opposed to vendor prefixed) HTML & CSS. ESPN invested a reasonable level of resources to do that and delivered a delightful experience to its users. I’ve definitely started to see the site pinned to Start around here, and I wouldn’t be surprised if our senior managers are secretly checking ESPN during meetings.

Here’s a before (left) and after (right) screenshot of the experience on Windows Phone 7.5. We want to say thanks to ESPN, and we look forward to seeing more rich experiences light up!

image     image

Special thanks to Krys Krycinski, Mike Marrone, and James Ballow at ESPN.

Amin Lakhani
Program Manager, Windows Phone