Pretty much; unless Javascript has an Array.copy() function or similar... inbuilt functions might be better optimized, but I doubt it'll make much difference in this case.

.. well, according to this page, one can hijack the Array.slice() method ( which is supposed to return a copy of a segment of an array ) to copy the whole Array.. I really don't know if that would be any more efficient than manual copying, but maybe it's worth a benchmark if you need the speed:

http://www.sematopia.com/?p=12
( Read the comments; the original poster seems to have ommited a neccessary parameter, and someone there explains what happens if you copy arrays of arrays or other arrays of references with .slice(); if you do so, you might want to do it manually, just to retain control )