Adding items to an object through the .push() method

.push() is a method of the Built-in Array Object

It is not related to jQuery in any way.

You are defining a literal Object with

// Objectvar stuff = {};

You can define a literal Array like this

// Arrayvar stuff = [];

then

stuff.push(element);

Arrays actually get their bracket syntax stuff[index] inherited from their parent, the Object. This is why you are able to use it the way you are in your first example.

This is often used for effortless reflection for dynamically accessing properties

stuff = {}; // Objectstuff['prop'] = 'value'; // assign property of an                          // Object via bracket syntaxstuff.prop === stuff['prop']; // true

so it's easy)))

Watch this...

    var stuff = {};    $('input[type=checkbox]').each(function(i, e) {        stuff[i] = e.checked;    });

And you will have:

Object {0: true, 1: false, 2: false, 3: false}

Or:

$('input[type=checkbox]').each(function(i, e) {    stuff['row'+i] = e.checked;});

You will have:

Object {row0: true, row1: false, row2: false, row3: false}

Or:

$('input[type=checkbox]').each(function(i, e) {    stuff[e.className+i] = e.checked;});

You will have:

Object {checkbox0: true, checkbox1: false, checkbox2: false, checkbox3: false}

stuff is an object and push is a method of an array. So you cannot use stuff.push(..).

Lets say you define stuff as an array stuff = []; then you can call push method on it.

This works because the object[key/value] is well formed.

stuff.push( {'name':$(this).attr('checked')} );

Whereas this will not work because the object is not well formed.

stuff.push( {$(this).attr('value'):$(this).attr('checked')} );

This works because we are treating stuff as an associative array and added values to it

stuff[$(this).attr('value')] = $(this).attr('checked');