jquery and jacascript object

i wanna get a form use jquery selector and reset this form,when i use $("#formId").reset (),it do not works.when i serch the reason in the internet ,i find object is encapsulated bt jquery , the reset() method must be a original javascript method,so the jquery object must be transformed to a original javascript object by [0],so at last i use $("#formId")[0].reset() and success.now what i think is the other methods like submit() should use like this as i have seen one of my colleague use submit() method like my first method but success to submit()!