Since the Date constructor is based on your PC’s timezone and server-side is obviously dependent on the server’s time settings…
What procedures can I do to ensure that the timestamps I generate are consistent on both ends?
I have a jQuery datepicker setup and I do a lot of work, I also have my own datepicker that’s generated from server-side code which looks up db availability for bookings.
I’m saving arrival/departure times on the server-side and the days are off by one because the JS is local timezone ( mine is Eastern ) .
Is my only option doing something like making the JS call PHP to grab a timestamp?
You could have your client query the server once at startup to get the server’s time, then calculate the difference between the time on the client and the time reported by the server. Cache this value, and use it for future requests. You may still be off by a few seconds (owing to the request latency), but you’ll be pretty close.