Autocomplete, clearing form values and Drupal form fields

<?php
/**
 * Implementation of hook_form()
 */
function mymodule_form() {
	$form['old_password'] = array(
		'#title' => t('Old Password'),
		'#type' => 'textfield',
		'#attributes' => array('autocomplete' =>'off'),
		'#required' => TRUE,
	);
	$form['new_password'] = array(
		'#type' => 'password_confirm',
		'#attributes' => array('autocomplete' =>'off'),
		'#required' => TRUE,
	);
	$form['submit'] = array(
		'#type' => 'submit',
		'#value' => t('Submit'),
	);
	$form['clear'] = array(
		'#type' => 'button',
		'#value' => t('Clear'),
		'#attributes' => array('onclick' => 'this.form.reset(); return false;'),
	);
	return $form;
}