Q:

does the javascript date object use the system clock?

e.g., if you had:
var d = new Date();
alert(d.getTime());

is it based on the system clock? if i change the time/date on my computer's clock, am i potentially sending erroneous data back to my server?

A:

This uses the system time on the client computer where this javascript is executed. So if you change the date/time on the client computer it will send the new value to the server.

