For development purposes, I need to disable the same-origin policy in Safari (on Windows) on my machine.
In Chrome, this can be done by launching with the flag
Later versions of Safari allow you to Disable Cross-Origin Restrictions. Just enable the developer menu from Preferences >> Advanced, and select "Disable Cross-Origin Restrictions" from the develop menu.
If you want local only, then you only need to enable the developer menu, and select "Disable local file restrictions" from the develop menu.