On this topic: I've encountered multiple small business websites that have a spam JavaScript redirect that on a referral from google.com -- if you go directly to the website (as the business owner or the GoogleBot might), everything is fine, if you click out from Google you get served either a small page with nothing both the JavaScript redirect, or the page with the JavaScript redirect prepended.
Some variants of this use cookies to only serve the redirect on the first click from Google, so if you're like "weird" and try again, everything looks fine the second time.
You can see the problem if you curl such a URL with Google as the referrer.
Some variants of this use cookies to only serve the redirect on the first click from Google, so if you're like "weird" and try again, everything looks fine the second time.
You can see the problem if you curl such a URL with Google as the referrer.