I have some asp code that pops up a calendar and allows the user to scroll months, and to choose a date.

The web form shows a start date and an end date.
There is a submit button, that calls up a result form to show the values picked in the two date fields.

We are on Australian DD/MM/YYYY format.

The code runs ok on my collegue's server, but when I run it on my server (windows 2000 server) and on my laptop (XP professional) there appears to be a date format issue.

I have checked the region settings and the custom formats (XP) on my operating systems but they were as expected.

I believe the Dateadd function is processing dates as mm/dd/yyyy.

Assuming the operating system dates are ok, is there a javascript / asp / IIS date format setting I should be aware of?

To be honest I don't understand my problem, I have manipulated the code and have the calendar half working, but I don't know what I should be fixing.

The collegue mentioned that the operating system date is all that should be set, and the programs will use it as the default format.
I am not sure about this?

Any advice or explanations are welcomed.