I am creating a login form for Parent/Teacher conferences. When the form loads I write the current time a hidden text field on the form bound to the table's 'time in' field. I would like to place a control on the form to allow users to select how long they expect the conference to last. They can select this time and submit the form. The idea is that if the Parent selects, say, 1 hour, then I would add one hour to the current time on the submit button's onclick event.
I was thinking about using a combo box with times in 15min increments. So if the parent/teacher conference will last 30 minutes users would select the second item. How would I then add 30 minutes to the 'time in' time value and then write that value to the table's 'time out' field?
A conference would not be more that four hours so a combo box should work unless you can suggest a better approach.