/**
* Writes a cancel button and invokes a cancel operation (eg a checkin).
*
* @param string $task An override for the task.
* @param string $alt An override for the alt text.
*
* @return void
*
* @since 1.5
*/
public static function cancel($task = 'cancel', $alt = 'JTOOLBAR_CANCEL')
{
$bar = Toolbar::getInstance('toolbar');
// Add a cancel button.
$bar->appendButton('Standard', 'cancel', $alt, $task, false);
}