Question: I know this isn't a code issue related question, but it's something I'd love to know and it may help others:

What's the difference between using this:

```
$(function() {
    var $fullArea = $('#full-sized-area');
    var $fullContent = $('#full-sized-content', $fullArea);
});

```

Over say this:

```
$(function() {
    var $fullArea = $('#full-sized-area');
    var $fullContent = $('#full-sized-content, #full-sized-area');
});

```

Answer: 
There is a difference,

**[Demo : Multiple selector](http://jsfiddle.net/93k2t/)**

```
var $fullContent = $('#full-sized-content, #full-sized-area');

```

Selects both the elements - **[Multiple selector](http://api.jquery.com/multiple-selector/)**: `$('#elem1,#elem2,...')`

---

**[Demo: Parent-child](http://jsfiddle.net/93k2t/1/)**

```
var $fullContent = $('#full-sized-content', $fullArea);

```

In this case : `#full-sized-content` has to the child of `#full-sized-area`

So its is equivalent to 

```
$('#full-sized-area #full-sized-content');
          Parent          Child                

```
Both are diffent here..

```
$(function() {
    var $fullArea = $('#full-sized-area');
    var $fullContent = $('#full-sized-content', $fullArea);
});

```

This one select element which has id "full-sized-content" under the #full-sized-area element

```
$(function() {
    var $fullArea = $('#full-sized-area');
    var $fullContent = $('#full-sized-content, #full-sized-area');
});

```

This one select both element with the ID full-sized-content and full-sized-area