JSON properties
- messageVersion
- name
- offset
- orientation
- pageHeight
- pageWidth
- position
- referrer (Screenview)
- referrer (webEnvironment)
- relXY
- root
- screenviewOffset
- scrollX
- scrollY
- serialNumber
- startTime
- subType
- target
- timezoneOffset
- type (message)
- type (event)
- type (target)
- url
- viewPortHeight
- viewPortWidth
- viewPortX
- viewPortY
- viewTime
- webviewId
- width