When a salaried employee who is paid semi-monthly quits in the first week of the two week pay period, would they still be paid for two weeks or just up to the day they quit?

Your salary would be prorated back to the day you quit. The employer does not have to pay you for the full payperiod only for the time you have worked. You cannot be docked for partial days so if you quit in the middle of a day you must be paid for the entire day.

Shirley