There're many things you can do.
For example, if you disable javascript on your browser and you go to our web site:
http://software.xfx.net/ you will see an error.
Others simply redirect you somewhere else... with a lightweight version of the web site.
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What percentage of the Internet users do you think browse the internet with JS turned off?
Do you really care missing those 20 users?

Do you really think these users will be able to make their way to your web site with JS disabled?
...knowing that they won't be able to use most search engines, won't be able to use 85% of the web sites on the internet, won't be able to... well... browse at all!
I really wonder... how far can you get with JS disabled!