get value of a custom attribute value

Hi

I have a custom attribute like below:

```
                        <select>
                            <option data-customattribute="custom attribute" value="599wa">value</option>
                        </select>
```

how to get value of data-customatribute?

with below snippet not work:

``` js
$('select').change(function () {
$(this).children("option").data("customattribute");
}
```
