View source for Tracking based on query string values

==What this article answers==
* You have a page which shows videos and you want to track whether the video was watched or not, and you only have a redirect link available
* You wish to only track an action when a particular query string appears in the URL
* You need to extract query string values and pass them to ConversionRuler for tracking

==Video Redirect or Query String Check==

Regarding the video redirect; say your page is:

 http://www.example.com/video.php 

Then you redirect to

 http://www.example.com/video.php?watched=1

The following JavaScript will track in lieu of the regular snippet:

 <nowiki><script type="text/javascript"><!-- ConversionRuler snippet here --></script>
<script type="text/javascript">
if (__CR.query("watched")) { __CR.track('XXXX'); } else { __CR.track('0'); }
</script></nowiki>

Where XXXX is the action code.

==Passing Query String Values for tracking==

Say the user's email address should be tracked on an unsubscribe page:

 http://www.example.com/unsub.asp?email=someone@example.com

To record the email address when this happens:

 <nowiki><script type="text/javascript"><!-- ConversionRuler snippet here --></script><script type="text/javascript">
if (__CR) { __CR.track('XXXX','', __CR.query('email','-No email-'));}
</script></nowiki>

=CR_QS API call=

If ConversionRuler snippets are loaded, '''__CR.query''' is a [[JavaScript]] function with the following syntax:

 function __CR.query(query_string_name, default_value=null)

It searches the current page for a query string (case-insensitive) and returns the value, or the '''default_value''' if not found.