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: 
Both are quite difference. 

Basically you are using [Multiple Selector (“selector1, selector2, selectorN”)](http://api.jquery.com/multiple-selector/) in the following line. So its simple

```
$('#full-sized-content, #full-sized-area')

```

Where as in line you are using context based selector, Here you are selecting element with ID `full-sized-content` in childs of `$fullArea` 

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

```

is equivalent to 

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

```

Note As IDs must be unique in HTML you can simply use

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

```
Your code:

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

```

it says find me `#full-sized-content` in `$fullArea`, because of the `,`. `,` makes a context for this.

---

This code:

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

```

is usually called a **muliple selector selection** which is a string with `,` separated elems while below 

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

```

is usually finds an element in a given context which is `,` separated elems.