Use a third-party ad tag without document.write. Otherwise, the third-party tag isn't executed.

To substitute a random number, use the %system.random% macro.

You can use macros in tags that are installed in the backup ad. A macro is a variable that returns data about an object (banner, campaign, site, placement, or some values obtained from a site page request) to the banner or backup ad code. For a list of macros, see Help.

<p>Placement ID: %place.id%</p>
The %place.id% macro substitutes the ID of the ad placement where the request was made in the banner code.
<p>Placement ID: 884617</p>

1. Install macros directly into the code that's forwarded.
2. Click "Encode".