How to copyright the design of a website ? (in particular, html websites, which are too easy to copy). And what are the actions that can be taken if someone has copied it? Can we bring there whole website down or only the copied design will be asked/forced to changed/removed?
Copyright exists from the time of creation. If you mean you want to prove that you created it on X date, as opposed to your competitor who claims that he created it on Y date, allow me to shamelessly self-promote my blog and suggest that you read about the WGA registration system: http://www.cyberlawfacts.com/2009/11/writers-guild-of-america-script.html Many countries also have a system set up to register your copyright, which creates a rebuttable presumption that you created the content. As turbovps said, use a DMCA notice if the host is in the United States. Laws vary outside of the United States as to what is required in terms of takedown notices. I have a DMCA notice generator in my signature line.
If you are in India, then its really hard to get copyright of your website. All you need put some script like disable right click. Make your website in php, which is hard to download, as compare to css/html website
As far as U.S. Copyright, you could get an official copyright if you pay for it and send in your code and/or documentation of your web page design.