Script to add a value for supporter_action.tracking_code. The value is added using a SalsaScript that appears in the page that follows the action. The example is coded to work with thank you pages. Change the logic to use any other page you like.

supporter_action_tracking_code.html

<?
    // Submit tracking_code to the supporter_action table.  Uses the contents of
    // the URL to submit supporter_action.tracking code for qualifying thank you pages.
    // Customization:
    // Change line 7 to be a comma-separated list of page keys.  (no spaces)
    // Change line 8 to choose the page type and retrieve the page key of interest.
    (function() {
        // Comma-separated list of thank you pages where this script will run.
        var validKeys = '547'.split(',');
        var pageKey = Request.getParameter('thank_you_page_KEY');
        if (pageKey == null) return;
        if (validKeys.indexOf(pageKey) == -1) return;

        var supporterActionKey = Request.getParameter('supporter_action_KEY');
        if (supporterActionKey == null) return;
        var track = Request.getParameter('track');
        if (track == null) return;
        DB.saveObject('supporter_action', { tracking_code: track }, supporterActionKey);
    })();
?>