For "page", are you referring to a web page? Would you mind to clarify which programming language edition of ChartDirector you are using, and the web framework you are using?
For the web edition of the "Programmable Track Cursor" sample code, when the web page is loaded, it will set up the "MouseMovePlotArea" event handler for the WebChartViewer.
If you have multiple charts on the same page, you will have multiple WebChartViewer objects. In this case, you just need to set up the "MouseMovePlotArea" event handlers for all your WebChartViewer objects.
If you need an example, please let me know your programming language and web framework.