Does javascript handle objects by reference or by value?

Question

I have this code

var myObjects = {}; //global variable

//Later on in the code:
for (i in myObjects)
{
    var obj = myObjects[i];
    process(obj);
}

function process(obj)
{
    $.getJSON("example.com/process/", {id: obj.id}, function(result)
      {
          //Will the following change the permanent/global copy e.g 
          // myObjects[44] ?
          obj.addItem(result.id, result.name, result.number);
      }
    );
}

Will the following line:

     obj.addItem(result.id, result.name, result.number);

modify the object by value or by reference, i.e will it modify the local copy of obj or e.g myObjects[44]?

If it affects only the local copy, how can I have it change the global copy of the object?

Answer 1

Primitive variables are passed by value in JavaScript, but objects are passed by reference.

Source and further reading:

• JavaScript: Passing by Value or by Reference

Answer 2

all non-object variables are pass-by-value afaik..