The position of Save and Cancel is no longer a matter of logic, only
of convention. The best would be to detect which operating system the
visitor is using and place the buttons accordingly. Second best option
is to find out which operating system is used by the majority of the
user base, and follow that convention.
Both Microsoft and Apple offer excellent User Interface Guidelines.
It's advisable to follow the guidelines unless you can motivate why
deviating is better.