[jQuery] how to get one class from a multi-class element?

[cherry.aus...@gmail.com]

I'm getting all knotted up on this!

I'm looking to use one class, from an element with several, as a
selector.
Example:

<div class="red tiny bold">
<p class="tiny">

target = $( 'div' ).attr( 'class' );
// get 'tiny' from returned value
$( "'p." + target + "'" ).doSomething();

How to I get jQuery to pick out just the class I need?