New IE8 features will break the JS on IE7/6. The features have a very big positive impact on performance, we would benefit a lot from them. I'm asking how committed we are with IE8 in D8.
How painful we want to make IE6/7 support for contrib. In order of PITA: to support IE6/7 contrib would have to:
- Replace files: Replace all problematic core js files with compatible version.
- Preprocess files: Preprocess the js file and do a search/replace (It'll be possible to do, it's just changing the function name with $).
- Replace functions: Replace a few core JS functions to replace them with compatible alternatives.
I need both answers to continue with the Core clean-up of JS files.
Drupal 8 will support only IE8+, this is great news. The real world may have to support IE6/7 for a while longer though.
IE8 allows us to use very nice things like
JSON. A number of these new things can speed up js so much it needs to be plotted on a logarithmic scale (true story). I very much intend to use them as much as possible.
Using that means that the page completely fails in IE6/7. Since the front-end might depend on some core code and said front-end might need to be IE6/7 compatible, how are we going to handle that? It's not the same as requiring a minimum PHP version.
On the code side we can wrap all functionalities in a function call that can be overridden by contrib. Honestly I'd prefer if we let contrib deal with that (backport module?) and override the whole js file to make it compatible for dumb browsers.
It's critical because in China for example they are still using IE6 an it still has a big market share. Even a few market share % correspond to a lot of people over there, we can't just ignore that.
Since D8 is still a while away maybe this can be postponed for later, but not too much, I, at least, will get to refactoring core JS pretty soon I'll need to know how we handle this.