checkbox problem

Hi friends,
Need a little help from experts.
I want to set the property onclick=functions(); for a check box in my form.
Is there a way to do it.So far,I am not able to see any property like this.
Below is my checkbox code.

$form['status_'.$i] = array(
                                    '#type' => 'checkbox',
				    '#return_value' => 1,
				    '#default_value' => 0,
				   );

Thanking you all.