Multiple select updates

Hi, I have a multiple select drop down where users can select or deselect items. So, if a user has three items selected from a previously saved report,and then decides to remove one, there are two left. I was going to compare what was there originally and after the users changes items, and compare the values. What is not selected i would delete and add new items if necessary using stored procedures. Is this he correct way to do this or is there a better way? . . Thanks