You also can use closure to "store" data while creating your markers.
This is the way i do it in my plugin for jquery (http://gmap3.net) This is used to store "drive" and "name" on the clustering example : http://gmap3.net/examples/clustering.html and on http://gmap3.net/api/add-markers.html to store a custom string to display on mouse over JB -- You received this message because you are subscribed to the Google Groups "Google Maps JavaScript API v3" group. To view this discussion on the web visit https://groups.google.com/d/msg/google-maps-js-api-v3/-/IKpkHk635eoJ. To post to this group, send email to google-maps-js-api-v3@googlegroups.com. To unsubscribe from this group, send email to google-maps-js-api-v3+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-maps-js-api-v3?hl=en.