No assignment of the salary or wages of any married person is valid for any purpose unless the assignment is in writing signed by the person’s spouse, if the spouse at the time is a member of the family, and unless the spouse’s signature is witnessed by 2 disinterested witnesses. No assignment of the salary or wages of any person is valid as to any such salary or wages accruing more than 6 months after the date of the making of the assignment, except that any assignment of wages made in connection with a proceeding under s. 128.21 shall run concurrently with the period during which the amortization proceedings are in effect and shall become void upon the dismissal of the proceedings. Nothing in this section shall apply to assignments made under s. 109.09 or ch. 767, nor to any authorization from an employee to an employer directing deductions from wages to accrue in the future for union or employee club dues, insurance or annuities, war bond purchases, a revocable and voluntary deduction to a credit union or a state chartered financial institution operated primarily for the benefit of the employees of any particular employer or other financial institution under s. 705.01 (3), for contributions to the American Red Cross, a community fund or other similar charity, or any indebtedness to the employer. No assignment of salary or wages or voluntary deduction which is permitted under this section shall be valid if prohibited by s. 422.404.