Extending/overriding in JavaScript?

I want to write a small game using JavaScript and <canvas> but first I want to nail the "correct" or at least common approach to working with Objects.

One topic I am having trouble understanding in particular is how I could implement overriding of method.

When I create an Object, I may have this:

function MyObject()
 {
     var base = {};
 
     base.i = 0;
     base.update = function()
     {
         base.i ++;
     }
 
    return base;
 }
 

Then when I create another Object that should start with the same members, I use this:

function AnotherObject()
 {
     var base = new MyObject();
 
     base.j = 0;
 
     return base;
 }
 

I want to add more content to AnotherObject.update() while still running the logic I have in MyObject.update(), but when I do this within AnotherObject():

base.update = function()
 {
     j ++;
 }
 

Then I of course lose the logic I added in MyObject.update().

How can I write AnotherObject.update() so that it also calls the original update() method defined by MyObject?

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