I am currently using this WordPress plugin, which uses JavaScript to prevent users to access the site contents.
Will search engines be able to read the content and index my site? Will it hurt my SEO?
Search engines will access the site content just fine, and so will users who want to steal your content (all they have to do is either disable javascript or view the source code - and "professionals" know that) and so will the automated crawlers that usually do the scraping and reposting thing...
It would hurt usability - sometimes people may want to copy text or simply right click for very legitimate reasons. Now. usability is a factor for SEO but is this particular thing an issue? Likely not, but one can never know.
It does give you a little piece of mind that you tried to protect your copyright and it does give those who manually copy text for reposting a sort of warning that you're serious about it, but that's about all.
I would say only do it if there are few people who steal your content constantly and you know that they are much too stupid to figure out the workaraunds.
