With this type of markup :

<input type="text" list="choices">

<datalist id="choices">

<option value="choice">choice</option>

</datalist>

And this jquery code :

$('input').attr('list')

On FF4 and Opera (which implement <datalist>) :

This call return <datalist id="choices"> and not "choices".

So it's impossible to change the attribute value.

It's important to note that "$('input')[0].list" returns also the datalist element and not the attribute value.

On other browsers (which do not implement <datalist>) :

This call return "choices", the attribute value.

For me it's a bug because it differs from all element attributes value get. But with FF4 and Opera behaving in a similar way it can be spec related.