CF7 cannot delete messages with reset button

Hi,I open a form within thickbox and all OK. I have included a submit button, reset button and close button (to close thickbox overlay). The problem I have is that if the user does not submit successfully, then the reset button does not remove the error messages and when I close the thickbox and reopen, the error messages are still there. Ideally I would like to have just 2 buttons, “submit” (if succesful closes form with thankyou message, if not successful then error messages) and “cancel” button to reset all fields, remove all errors messages and close thickbox overlay. I assume this is possible with scripts, but unfortunately I don’t know how! Any help would be enormously appreciated. Many thanks

http://ww.wp.xz.cn/extend/plugins/contact-form-7/