$data = $this->Js->get('#Form')->serializeForm(array('isForm' => true, 'inline' => true)

$.unserialize('.$data.') // I work with CakePhp so I can use variables ;)

Object {_method: "POST", data[Rating][itemtype]: "Upload", data[Rating][itemid]: "73", data[Rating][rate]: "4"}

$.unserialize('.$data.')._method // Output: POST

$.unserialize('.$data.').data[Rating][itemtype] // Mark up the '[' and ']'