Hands-on module
Cross-boundary tracking
Keep one session alive across domains and bridge events out of iframes.
Real journeys cross boundaries: a visitor moves from your marketing site to a checkout on another domain, or interacts with a widget sealed inside an iframe. Both break tracking unless you bridge them.
You'll configure cross-domain measurement so the GA4 session survives the hop to a second domain, then relay an event out of an iframe into the parent dataLayer with postMessage.
What you'll learn
- Configure cross-domain measurement in the Google tag (the linker)
- Confirm the _gl parameter carries the session across domains
- Relay an iframe's event to the parent page with postMessage
- Fire a tag on the relayed event (and why you validate event.origin)
Start lesson 13 lessons · self-paced