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I'm trying to improve my understanding of the global namespace in javascript and I'm curious about a few things:
is there a "GOD" (i.e. a parent) object that all objects (since all things except primitives are objects) to answer to and if so would that object be "window" ?
why is it bad idea to have vars/functions on a global level?
if it is really a bad idea to have vars/functions in global scope then would closures be the best way to avoid this? example:
function parent(){ var x = 'some value';//this var would be considered global to all children functions but not in the true global namespace function child1(){ x.someMethod() } function child2(){ x*something; } function child3(){ x+=something; child2() child1() } child3() } parent() 
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The global namespace is the top space of Javascript that contains the variables. In a browser, it's known as the window.
A closure is the combination of a function bundled together (enclosed) with references to its surrounding state (the lexical environment). In other words, a closure gives you access to an outer function's scope from an inner function.
Namespace refers to the programming paradigm of providing scope to the identifiers (names of types, functions, variables, etc) to prevent collisions between them. For instance, the same variable name might be required in a program in different contexts.
In JavaScript, closures are the primary mechanism used to enable data privacy. When you use closures for data privacy, the enclosed variables are only in scope within the containing (outer) function. You can't get at the data from an outside scope except through the object's privileged methods.
Is there a god (i.e. a parent) object?
Yes. More technically, it's the global object that all these primitives are members of; it just happens that in the browser, the window object is the global object.
> window.String === String; true Why is it bad idea to have vars/functions on a global level?
Because if you're adding lots of 3rd party libraries/ scripts, they all share the same global object, there's the chance of name collisions. This is a real life problem with all the libraries which use $ as an alias (jQuery, Prototype and more).
If it is really a bad idea to have vars/functions in global scope then would closures be the best way to avoid this?
x shouldn't be considered global. It's part of the closure formed by declaring the child functions inside the parent() function. The problem part of your snippet is that parent() is global; what happens if some other code re-declared parent()? This would be better:
(function () { function parent(){ var x = 'some value'; function child1(){ x.someMethod() } function child2(){ x*something; } function child3(){ x+=something; child2() child1() } child3() } parent() }()); The fact x is accessible within the child functions isn't bad; you should have written those functions yourself, so you should be aware of the existence of x. Bear in mind that if you re-declare x within those child functions with var, you won't affect the x in parent().
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