Duplicate content resulting from js redirect?
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I recently created a cname (e.g. m.client-site .com) and added some js (supplied by
mobile site vendor to the head which is designed to detect if the user agent is a mobi device or not. This is part of the js:
var CurrentUrl = location.href var noredirect = document.location.search; if (noredirect.indexOf("no_redirect=true") < 0){ if ((navigator.userAgent.match(/(iPhone|iPod|BlackBerry|Android.*Mobile|webOS|Window
Now... Webmaster Tools is indicating 2 url versions for each page on the site - for example:
1.) /content-page.html
2.) /content-page.html?no_redirect=true
and resulting in duplicate page titles and meta descriptions.
I am not quite adept enough at either js or htaccess to really grasp what's going on here... so an explanation of why this is occurring and how to deal with it would be appreciated!
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The easiest way to fix this is to tell google to ignore the URL variable no_redirect . You can do this in webmaster tools under Configuration > URL parameters. find where no_redirect is listed, click edit and set it to "used for tracking".
Remember to do similar for bing.
You could also block these in robots.txt
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Hi Mat,
Thanks for the response!
I am really trying to understand what is occurring here and how to remedy via js or htaccess.
Can you please provide further insight?
Thank you.
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I'm not great with JS myself - I'm lucky enough to employ people to do that for me! However, here is what the script is doing:
- First check whether "no_direct=true" has been set - presumably to allow users to override the mobile version and view the full desktop version if they choose
- If that hasn't been set then look to see if they are using iPhone/iPod/Blackberry/Android browsers
- Presumably the next line is then redirecting.
That seems fairly logical - no real problem there. However the mobile version is getting picked up and indexed somewhere.
Because you want users to have access to that "duplicate" version, but don't want the search engines too you don't really want to either prevent this URL from existing or override it with .htaccess . It would be smarter to pick a method that targets the search engines, such as:
- Stop them crawling it (through webmaster tools or robots.txt)
- Add a no-index tag to it
- Canonical it back to the main content
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That makes perfect sense. I think I will try instructing webmaster to ignore the variable as you initially suggested. It's the quickest approach

Thank you very much for your time and wisdom - much appreciated!
Dino
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You're welcome