spidermonkey global object image

Question

I've been reading spidermonkey doc (SpiderMonkey - JSAPI User Guide) and feel kind hard to understand how the relationship betbetween global object and all the variable and functions.

Say I have the code below in test.js:

var Global_Var1 = 1;
var Global_Var2 = 2;
var Global_Func1 = function() {};
var Global_Func2 = function() {};

var Namespace_N1 = Namespace_N1 || {};
var Namespace_N2 = Namespace_N2 || {};

Namespace_N1.functionN1 = function() {};
Namespace_N2.functionN1 = function() {};

and what will be inside the spidermonkey's "global object" at runtime? will it be something like (a tree view):

Global Object (JS::RootedObject, JSClass)
     - Global_Var1 (as object property ? with value 1)
     - Global_Var2 (as object property ? with value 2)
     - Global_Func1 (as object property ? whose value is function)
     - Global_Func2 (as object property ? whose value is function)
     - Namespace_N1 (as object property ?)
             - functionN1
     - Namespace_N2 (as object property ?)
             - functionN1

Any information on this topic will be appreciated, thanks :)

Answer 1

Global object is indeed an object. For example, in the context of a browser, window is the global object. Evaluating var a = 1; in the global scope is equivalent to setting the property a of window to 1, i.e. window.a = 1;.

The documentation of JS_InitStandardClasses says that initialization of a JS context requires you to give an object as the global object. Existing properties of the given object become global variables, and JS_InitStandardClasses will add standard global properties (such as Array, Date, encodeURIComponent) to the given object.