Please forgive me my near-off-topic answer: Sure there are users out there without JS. There are still some IE6 users out there. But in most cases you need jus

Please forgive me my near-off-topic answer: Sure there are users out there without JS. There are still some IE6 users out there. But in most cases you need just look at your target: If you build a SaaS service you probably focus on the early adopters, first movers or whatever you call them. Old browser or obscure security settings are a niche. If your product focus on that niche - great, consider it in your technical setup. After attending a horrible freelance project as a ruby/rails guy in 2009 I finally made a decision for all of my hopefully upcoming projects: * focus on the early adopters who may understand your product without a big introduction. these people usually have the best and modern browsers available. * optimize for Safari/Mac, Firefox and maybe Chrome * optimize only for iPhone * forget the rest until you have 100 paying customers. Then decide again. (100 is just a number, maybe 50, maybe 1000 — you decided) BUT: If you know for sure, that most of your taget customers are using IE6/have no javascript support/whatever: Support it. But I doubt it. And don't think that your startup will have the same % amounts of browsers/settings like the big sites on the web. Also keep in mind that people need to be able and willing to spend money. I can imagine someone without javascript and cookies will never (be able to) enter her/his payment information over the web into a form. They'll be very conservative and in my opinion it's not worth the time to try to "convert" them. TL;DR Try to focus the easiest reachable solution only. Know your potential customer's setup. Be selective.