Publish URL in preview

The preview Helper allows you to output content only in Preview.

It's used like:

{{#preview}}    
     <p><strong>Channel name:</strong> {{channelName}}<br>
     <strong>Section name:</strong> {{sectionName}}<br>
     <strong>Publish URL:</strong> {{ publishURL }}</p>
  {{else}}
     <!-- Output something to the published page -->
{{/preview}}