[sourcecode lang=“javascript” gist=“1002886”]var M = function() { this.m = function() { return 42 } };

var inst = new M();

inst.f = function() { return 42 };

// How to tell that f is a function in a field and // m is a method in an arbitrary object? // // example:

is_method(inst.f); //=> false

is_method(inst.m); //=> true

// Is it possible to write is_method? [/sourcecode]