It seemed like a good idea to some Microsoft developers (for a brief moment): Why not add support for both the -ms and -webkit prefixes in the version of the Internet Explorer (IE) mobile browser Microsoft was building for Windows Phone 7 devices?
It turns out the idea was a bad one. And it took Microsoft a single day to change its path, as documented in two back-to-back blog posts on the "IE for Windows Phone Team" blog.
A quick bit of background: Webkit is the rendering engine at the heart of a number of browsers, including those from Apple, Google, Nokia and RIM, among others. Microsoft uses its own rendering engine, known as Trident, inside Internet Explorer. When browser developers implement an experimental or proprietary CSS property, they prefix it with the appropriate “vendor prefix."
Community reaction was unfavorable (to put it mildly) about Microsoft's decision to add the -webkit prefix. Daniel Glazman, the co-chairman of the W3cCSS Working Group weighed in with the following comment (at the end of the original Microsoft blog post):
"Let me state it very clearly: vendor prefixes are here for experimental purposes by the vendor represented in the prefix. I __strongly__ recommend removing *immediately* that -webkit-* property from Mobile IE."
On May 11, the IE for Windows Phone Team did a 180. As explained in a new blog post by Marini:
"Our original intent in adding support for this WebKit-specific property was to make Web developers’ lives a bit easier by not having to add yet another vendor-prefixed CSS property to their pages to control how text was scaled. Even more specifically, we intuited that the most common use case for this property was to explicitly set it to 'none' in order to tell the browser not to scale a particular section of text....
"After hearing the community’s feedback on this issue (and a couple of face-palms when we realized the broader implications of implementing other browser vendors’ CSS properties), we’ve decided that it’s best to only implement the -ms- prefixed version and not the -webkit- one."
Microsoft is putting the finishing touches on the operating system that will power Windows Phone 7 devices. A near-final escrow build of the release candidate of the Windows Phone 7 OS leaked recently. Microsoft officials have declined to say when the company expects to release to manufacturing that operating system, but the first Windows Phone 7 devices are due out by this holiday season.