CFLib.org – Common Function Library Project

Description:
This UDF will return true if the user has opted out of tracking via the Do Not Track header. The "Do Not Track" HTTP header is a privacy option provided by some browsers indicating that the user has opted out of tracking (such as analytics or behavioural advertising).

Return Values:
Returns a boolean indicating if the header was found and set to 1

Example:

<cfif NOT hasDoNotTrackHeader()>
    <!--- Analytics code goes here --->
</cfif>

Parameters:

No arguments.

Full UDF Source:

/**
 * Support for the "Do Not Track" HTTP header
 * v1.0 by Indy Griffiths
 * v1.1 by Adam Cameron slight performance optimisation and rename
 * 
 * @return Returns a boolean indicating if the header was found and set to 1 
 * @author Indy Griffiths (indy@indygriffiths.com) 
 * @version 1.1, December 4, 2013 
 */
function hasDoNotTrackHeader() {
    var requestHeaders = getHttpRequestData().headers;
    return structKeyExists(requestHeaders, "DNT") && requestHeaders.DNT == 1;
}