window.toString overrides global toString

[Voxelot]

I'm currently in the process of porting env.js to Nashorn. While trying to run jQuery I discovered that the toString method in window.js (https://github.com/envjs/env-js/blob/master/envjs/window.js#L749) actually causes all objects to return '[Window]' when their toString method is called.

Chrome:

>toString()
"[object Window]"  
>toString.call("test")  
"[object String]"
>var a = {}
undefined
>a.toString()
"[object Object]"

Nashorn + env:

console.log(toString());
>>[Window]
console.log(toString.call("test"));
>>[Window]
var a = {};
console.log(a.toString());
>>[Window]

jQuery is unable to make ajax requests because the toString method is used when registering the transports (https://github.com/jquery/jquery/blob/master/src/ajax.js#L61). Since the toString method is broken, jQuery's "typeof" method will default to calling the transport functions objects which causes the "isFunction" check to fail, preventing any transports from being registered.