Try something like this:
function stopPropagation(myEvent){
if(!myEvent){
myEvent=window.event;
}
myEvent.cancelBubble=true;
if(myEvent.stopPropagation){
myEvent.stopPropagation();
}
}
google.maps.event.addDomListener(myHtmlElement, 'click',
function(myEvent){
stopPropagation(myEvent);
});
Martin.