VAST tracking events / NonLinear
expand VAST tracking event
Short answer: Removed in VAST 4.0. Use adExpand on 4.x tags. Removed in VAST 4.0.
Replacement: use adExpand on VAST 4.0 and later. A 4.x player that sees expand has no handler for it.
When it fires
Old name for the creative expanding. VAST 4.0 renamed it to adExpand so it is not confused with playerExpand (the player chrome growing). A 4.x player that sees expand has no handler for it.
expand was the creative, and 4.0 gave it a clearer name
expand fired when the creative itself grew, typically a NonLinear unit. VAST 4.0 removed it so it would not be confused with the player surface getting larger. The replacement is adExpand. playerExpand is the other rename, from fullscreen, and it is a different event.
A 4.x overlay that still says expand will not notify anyone when the creative grows. The interaction can still happen. The URL does not fire. Use adExpand and adCollapse as the pair.
Expand without a later collapse
On a 2.0 or 3.0 overlay, expand with no collapse means the creative grew and the session ended while it was large, or the collapse URL is missing. close may still fire if the viewer dismissed it from the expanded state. Do not require collapse before you believe expand.
When you move the document to 4.0, replace expand and collapse together. A 4.x player that still receives expand will show the larger creative and will not call the URL. The UI and the report diverge, and the report is the one that is wrong.
When the column stays empty
expand was removed in VAST 4.0. A document at that version can still contain the element, and the player has no handler, so the URL is never requested. The name that replaced it is adExpand.
Each wrapper hop may include its own expand URL. The player requests every one of them when the event happens, so a chain of four hops produces four calls for one playback. An http URL on an https page is dropped by the browser before the ad server sees a miss. The event name can be right and the scheme can still zero the column.
Where it is valid
| 2.0 | 3.0 | 4.0 | 4.1+ |
|---|---|---|---|
| Yes | Yes | Removed | Removed |
Legal containers: NonLinear. An event in the wrong container is not a player error. It is a URL nobody calls.
Using it in a tag
Put it in a NonLinear TrackingEvents block. It is not valid on the other creative types, and a player does not fire a tracker in the wrong container.
<NonLinear>
<TrackingEvents>
<Tracking event="expand">
<![CDATA[https://track.example.com/expand]]>
</Tracking>
</TrackingEvents>
</NonLinear>VAST XML fragment only. This excerpt belongs inside a complete VAST document, so standalone validation will fail until it is wrapped in a full <VAST>response.
Related vastlint rules
- VAST-4.0-tracking-event-removed: fullscreen/exitFullscreen tracking events were removed in VAST 4.0
- VAST-4.1-tracking-event-value: Tracking event attribute not in the valid set for this VAST version
Related events
- adExpand: Fires when the creative expands. 4.0+ name replacing expand.
- collapse: Removed in VAST 4.0. Use adCollapse on 4.x tags.
- adCollapse: Fires when the creative collapses after expand. 4.0+ name.
Check the XML, then confirm the beacons fire
Validate the event names and containers on the document. Test a live URL when the XML is clean and reporting is still empty.