The native JavaScript Date
system works in milliseconds as opposed to seconds, but otherwise, it is the same “epoch time” as in UNIX.
You can round down the fractions of a second and get the UNIX epoch by doing:
Math.floor(+new Date() / 1000)
Update: As Guillermo points out, an alternate syntax may be more readable:
Math.floor(new Date().getTime() / 1000)
The +
in the first example is a JavaScript quirk that forces evaluation as a number, which has the same effect of converting to milliseconds. The second version does this explicitly.