Setting additional parameters on form_dropdown

[eluser]Chris Williams[/eluser]
For a label to work when clicked, the field needs an ID. Also, I'd like to set a required param to this. How do I do this?

Code:

<label for="billing_state">State:</label>
      &lt;?php echo form_dropdown('billing_state',$options,set_value('billing_state',$billing_state)); ?&gt;