Hello,

I forked the repo about this, and just wanted to have your opinion on this before testing and proposing it :

https://github.com/mlbli/zepto/commit/8b140fd80e9a31b66832a9405a2c5907361571f3

The main goal of this part is to preserve prototypal inheritance with Zepto objects in IE :

On a "modern" browser :

var doc = $(document) 
doc.foo // undefined
$.fn.foo = "bar"
doc.foo // "bar"

With $.extend(dom, $.fn) in IE:

var doc = $(document) 
doc.foo // undefined
$.fn.foo = "bar"
doc.foo // undefined

The main bottleneck is that it uses another context for execution (via an iframe), so isArray mush use {}.toString instead of instanceof. Positive point though, isZ in IE can now use isPrototypeOf.

Thanks!