You should weigh the options and ask yourself:
1) what percentage of users will have javascript turned off. (according to this site, only 5% of the world has it turned off or not available.)
2) will those users be willing to turn it on
3) of those that aren't willing to turn it on, or switch to another browser or device that has javascript enabled, is the lost revenue more than the effort to build a separate non-javascript version?
Instinctively, I say most times the answer is no, don't waste the time building two sites.
