Events: Cross Domain Tracking

Cross-domain Tracking is a technique for measuring visitors that follow links between multiple websites on different top-level domains. 

When a user browsing website A clicks on a link pointing to website B, his user ID stored for Website A will be available for SDK deployed on Website B via a parameter in URL, hence it can be tracked and stitched to user ID stored for website B. 

SDK is now supporting this type of cross-domain tracking, but domains, where we want to pass user IDs, need to be whitelisted in SDK configuration.

Follow the steps described in the article How to deploy … and whitelist domains in

`MeiroEvents.init` function:

Before:
MeiroEvents.init(domain);

After:
MeiroEvents.init({ domain: domain, cross_domain_whitelist: [“example.com”] });

Whitelist should contain domain names for every website to which you want to append user id. 

Take a look at the following example:

We have site-one.com, site-two.com, and site-three.io, we want to implement cross-domain tracking for those domains. 

On site-one, the `cross_domain_whitelist` array will be `[“site-two.com”, “site_three.io”]`

On site-two the `cross_domain_whitelist` array will be `[“site-one.com”, “site-three.io]` 

On the latest website, the array will be `[“site-one.com”, site-two.com”]`

Each website needs to include other domains in the SDK configuration.