public static function start( $key, $attr = array() )
	{
		$attributes = array();

		// force the form role
		$attributes['role'] = 'form';

		if ( !is_null( $key ) )
		{
			 static::$id_prefix = $attributes['id'] = static::form_id( 'form', $key );
		}

		$attributes = array_merge( $attributes, $attr );

		return '<form'.HTML::attr( $attributes ).'>';
	}