It seems iOS6 has introduced a ‘bug’ in Ajax calls – specifically it caches any Ajax “POST” call so that subsequent reads access the cached file instead of the original on your website which you may have changed. The solution is to change the Ajax call just slightly so it is unique.
Here is a workaround that forces the Ajax call to access the original. The original code:
res=Ajax(filename,"POST")
The corrected code:
res=Ajax(filename,"POST","/no-cache?" & Date)
Thanks to Helen Sandoz for this tip!