How to tell search engines not to check a checkbox?

Question

How do I tell search engine crawlers not to check a checkbox when indexing my site? I want to do something like this:

<input type="checkbox" rel="nofollow" />

, but the rel attribute is not listed in the list of attributes here: The Input (Form Input) element, which makes sense, because this isn't a link. But I am not sure how to tell search engines that they shouldn't check this when filling out the form. If I include this rel="nofollow" attribute here, will search engines comply anyway, even though it is not valid?

Answer 1

It seems that Google only follows GET forms. So make it a POST.

That means that if a search form is forbidden in robots.txt, we won't crawl any of the URLs that a form would generate. Similarly, we only retrieve GET forms and avoid forms that require any kind of user information. For example, we omit any forms that have a password input or that use terms commonly associated with personal information such as logins, userids, contacts, etc. We are also mindful of the impact we can have on web sites and limit ourselves to a very small number of fetches for a given site.

From developers.google

For indexing different search results, I suggest the following approaches

1. Use different params or urls for different search results and put them in the sitemap and refer to them on a sacrificial or site-map page.
2. Detect that a robot is crawling and make some inputs read-only and autofill others to achieve different search results.

Answer 2

You can block Googlebot from crawling your forms by excluding them in your robots.txt file.