IbComposer_toggleMarker(mapId,layerName,markerName);

where:

mapId

Alphanumeric

Is the unique identifier of the map control. For example, mapcontrol1.

layerName

Alphanumeric

Is the unique identifier of a layer within the map. For example, Layer1.

markerName

Alphanumeric

Is the unique identifier of a marker within the map. For example, redpin.

function button1_onclick(event) {
   var eventObject = event ? event : window.event;
   var ctrl = eventObject.target ? eventObject.target :
   eventObject.srcElement;
   // TODO: Add your event handler code here
   IbComposer_toggleMarker('mapcontrol1','Stores','EMart');
}