Creating Basic Data-driven Combo Boxes?

Here is the link to a page on my work web: -

[URL]

You will see that I have three combo box objects on this form - one containing dates (Date) and the other two containing times (Time1 & Time2). Each time on each date is an available appointment.

I would like the content of the date combos to be read from a file whenever the page is opened - a text file with one record per row would be fine (by way of an example - but this may be insufficient). On the face of it this would seem fairly rudimentary but I don't code in JavaScript of PHP and, having found this site I can make a start. I used to be a VB coder.

On each date the following appointment times are available: -

10:00
11:00
12:00
14:00
15:00

This assumes that no appointments on a given day are taken.This leads me to conclude that each date should have records for each time - possibly as a CSV text file as follows: -

"29th May 2009","10:00"
"29th May 2009","11:00"
"29th May 2009","12:00"

[code]...

The second time combo should make unavailable the time selected in the first time combo and present only those times available on the chosen date in the CSV file on the server.When I confirm appointments, at present I have to edit the page objects and update the web - which is quite messy and slow whereas uploading a simple text file, whilst an imperfect solution, is much better than what I currently have.

I believe that a PHP or Javascript routine based on events on the three objects would remove the inherent problems and would provide a useful set of building blocks for other routines of a similar nature.The routine would trigger whenever the page is loaded (or refreshed) or the content of any one of the three objects gets or loses the focus or a selection is made in an object.

The Date Combo would need to look up the available dates - keeping the currently selected date selected or, if that date is no longer available defaulting to the first date in the list. The user then makes a selection or makes no change to the selected date.The Time1 Combo then reads the available times for that date, retains the currently selected time (if available) or the first available time (if the selected is not available) and the user makes a selection or accepts the current selection.The Time2 Combo does the same as the Time1 Combo and in addition it eliminates the time selected in the Time1 Combo from the available choices.

The result is that visitors are only offered available times on available dates (insofar as this solution provides).When the form is submitted I would receive the email and confirm the appointment with the client and, in addition, I would modify and upload the modified data file to the web server using Filezilla. The benefit is that there is a slim to none chance of two people wanting to book the same times on the same date at exactly the same time (though it is possible). In addition, I can add new dates and add new times if there is a demand and I can even add previously deleted times if there is sufficient demand to warrant bringing in a second consultant to take the meetings.