The goal is to be able to show a lot of static mappoints.
You can download the complete source, including the php scripts to handle the server side, here.
Note that this is just one example of how it can be done. There exists other methods (that use cookies, for example).
How it works
Ever looked at the wikipedia or panoramio layers in a google map and wondered how the hell they rendered so many points that fast? Well... they don't. Not really.
You're actually looking at a tile layer on the standard google tile layer:
My tile layer is dynamically loaded from a database and requested by GMap.
On request, the script also asks for the set of points that are located on the requested tile.
Both are downloaded and onmouseover every point is checked.
If the script detects it is hovering over a point, it changes the mouse cursor. In this example, on mouse over the point is also printed in the log.
This way it seems as if you're over a GMarker, while in fact you're not.
Please note that this is rather sloppy work. The mappoint detection can be sped up considerably, as well as several other things. This page simply serves as an example to those who are trying to accomplish the same.
Version 1.00, January 2009, qfox.nl