bound functions and instanceof

gistfile1.js

function f(){}
var g = f.bind({});

var newg = new g;
// call g.[[Construct]] (which is f.[[Construct]] per ES5.1 15.3.4.5 step 13)
// so, |new g| is the same as |new f|: an object which has f.prototype as [[Prototype]]

newg instanceof g;
// instanceof g calls the g.[[HasInstance]](newg) (please forgive my skip of reference/GetValue mess)
// As per ES5.1 - 15.3.4.5.3, g.[[HasInstance]](V) is g.[[TargetFunction]].[[HasInstance]](V)
// which is f.[[HasInstance]](V)
// ==> g.[[HasInstance]](newg) === f.[[HasInstance]](newg) === true

discussion continued at: https://gist.github.com/1149041