How to stop parameters page from being indexed

[thok]

I have a page http://www.example.com/login/

I want it to get indexed.

But I don't want any thing which is passing any parameter to get indexed as a separate page. Like I dont want following page to get indexed:

http://www.example.com/login/?action=register

[g1smd]

Try this in robots.txt:

User-Agent: *
Disallow: /*?action=

Be aware that if anything anywhere on the web links to URLs with parameters, the URL can still appear as a URL-only entry in the SERPs.

[topr8]

use the canonical tag

[googlewebmastercentral.blogspot.com...]