miscoded

How would Chris Wilson feel if people stopped writing him open letters?

I'm nowhere near Brendan's league but here's another "Dear Chris", this time on the proposed <meta http-equiv="X-UA-Compatible" content="IE=8" /> versioning for HTML5.

First: I know you're stuck between a rock and a hard place, between thousands of web developers shouting and swearing at you for not implementing the standards better and millions of web sites that might break if you do. Moreover, knowing first-hand the problems Opera ran into when implementing WebForms 2 I don't doubt for a moment that your compatibility concerns are real.

The proposed META tag sort of shifts maintenance and backwards compatibility concerns from website authors to browser developers, which can be a good thing. However, there are problems with such wholesale version targetting:

• Browsers will have to support an unmanageable and confusing mess of different rendering modes (and the PocketIE team will hate you for the bloat).
• Because the META tag affects every part of the page, progressively enhancing such pages with new CSS features will be harder.

The way the web currently works is partial versioning: using JavaScript object detection, conditional comments (IE-only), CSS hacks or special keywords to "opt in to" specific layout or scripting properties. Can we build on and extend that? Enhance feature detection rather than opt-in hard-coded rendering mode?

Some examples of what that might look like..

-moz-box-sizing equivalents for opting in to specific interpretations of given CSS properties

if( 'borderRadius' in element.currentStyle )

@supports-multiple-backgrounds{ div.mosaic{ bacground: URL(bg1.png) top left no-repeat; bacground: URL(bg2.png) bottom right no-repeat } }

I'd like markup or CSS to express "if you support css3-column-layout, fetch that stylesheet, else use this XSL transformation to build a TABLE".. So, feature-based versioning built right into the standard itself instead of added as a META hack and an afterthought. Please consider making the opt-in mechanisms feature-based rather than rendering-engine-version-based!

How can you do it? Well, the IE team may have forgotten what it takes to play catch-up with a different UA implementation (you had some experience back in the NS4 days though) but Opera QA can remind you . You could apply the same skills to align the new standard and the new rendering engine with the web:

The web and the spec would benefit enourmously if your team sat down to do the detailed analysis work - hunting through the sites that break, figuring out the main problems, suggesting ways the still-in-progress HTML5 standard could change to make real compatibility possible. It's slow but you can make a public comittment and draw huge grassroot support from web developers. I bet you would get help doing evangelism and outreach for sites that serve you "error correcting" CSS you can't possibly work with in standars mode. You can release IE8 beta versions but delay the final until site compatibility problems are resolved..

We at Opera doing this right now, spending hours analysing IE quirks to figure out how to be compatible with the specs, the web, and the IEs. It's slow. It takes manhours and manyears. But it's what it takes to do it right..

Software is 100% detail. Quality is 100% attention to detail. And the detail called X-UA-Compatible should be replaced with something better. Thanks for your attention.