Well, you have a bigger problem than that. Let's take your example, where--after someone selects a start time of 11:45 AM and a finish time of 12:45 PM--you change your start time list to:
.... 11:30AM 01:00PM .... What if the person selects 11:30 AM (completely valid), and then selects an end time of 12:00 PM, because they want a (completely valid) 30 minute time slot? If you have a variable length of appointment, then you are always going to have this problem; in more general terms, it is impossible to know for sure whether a start time is valid without also knowing the duration of the appointment desired. Likewise, it is impossible to know for sure whether an appointment length is valid without also knowing the desired start time. You could start by asking for the day and then the duration of appointment the user wants. Then you could figure out all of the possible start times during that day for an appointment of that duration. The logic of this last step depends a lot on how you store the data, I guess. But you can rely on this generalized idea: A start time ST on a day is valid for a given duration D if ST + D <= the next already used start time greater than ST. HTH, Matthieu -----Original Message----- From: Andy Mcshane [mailto:[EMAIL PROTECTED] Sent: Thursday, January 12, 2006 8:46 AM To: CF-Talk Subject: Calculate schedule timeslots I am sure that I saw something a while back that may address the issue I have. I have a scheduler that has time slots in increments of 15 minutes. What I need to do is to be able to exclude time slots that have already been allocated. For example I have start and end time dropdown lists so a user can select a time slot as follows; Start time : 11:45 AM Finish Time : 12:45PM Once this time slot has been allocated I need to be able to exclude this range from both of dropdown list i.e. Start time will now look as follows 11:30AM 01:00PM End time will be same. I already have the logic to ensure that the start and end time are not the same and also that the end time is after the start time but I am struggling to figure out how edit my dropdowns on the fly as time slots are allocated. Anybody help? Maybe a more simple method would be to only initially populate the start time dropdown and use the onchange method to populate the end time box? Would this be easier do you think? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Message: http://www.houseoffusion.com/lists.cfm/link=i:4:229513 Archives: http://www.houseoffusion.com/cf_lists/threads.cfm/4 Subscription: http://www.houseoffusion.com/lists.cfm/link=s:4 Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=89.70.4 Donations & Support: http://www.houseoffusion.com/tiny.cfm/54