title: jquery UI sortable: how can I change the appearance of the "placeholder" object?
body: <p>In the example given at <a href="http://jqueryui.com/demos/sortable/#placeholder" rel="noreferrer">http://jqueryui.com/demos/sortable/#placeholder</a> the placeholder is the orange box that appears when you drag any of the items.</p>
  
  <p>This element can be tweaked using the <code>placeholder</code> option -- but it only lets you modify the class of the element as described here: <a href="http://jqueryui.com/demos/sortable/#options" rel="noreferrer">http://jqueryui.com/demos/sortable/#options</a></p>
  
  <p>I would like to customize this element more, e.g. by supplying a function to the <code>placeholder</code> option in the same manner that one can supply a function to the <code>helper</code> option.  </p>
  
  <p>What would I need to change (e.g. in sortable.js) to do this?</p>