Handling ctrl+click on Google Maps

Question

I'm trying to make the user select multiple markers on my map by pressing control key and click on the marker.

For doing this, I write this code:

google.maps.event.addListener(marker, 'click', function (e) {
    // detect if is pressed ctrlKey or not to do stuff
}

In the GoogleMaps V3 docs there is no info or documentation about this e object, beyond the latLng property. But when I debug with Google Chrome, I see this Ra object that contains exactly what I needed. My question is, it is safe to hardcode this undocumented Ra access to obtain if ctrlKey is pressed?

Answer 1

As asked for in comment, what contains Ra that is important? My experience is, that google maps change those internal variable / object names constantly.

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However, had made a demo to show how to select multiple markers by holding ctrl down and clicking on the markers :

See fiddle -> http://jsfiddle.net/FbGa5/
Notice : You must activate the iframe by clicking on the map once before ctrl or any other keypress can be captured.

Keep track of the ctrl key :

var selecting = false,
    selectedMarkers = [];

window.onkeydown = function(e) {
  selecting = ((e.keyIdentifier == 'Control') || (e.ctrlKey == true));
}
window.onkeyup = function(e) {
  selecting = false;
}

Select markers if ctrl-key is down and a marker is clicked. If a marker is selected, it turns blue, if a marker is deselected it turns back to red :

google.maps.event.addListener(marker, 'click', function() {
   if (!selecting) return;
   var id = this.id;
   var index = selectedMarkers.indexOf(id);
   if (index>-1) {
     this.setIcon('https://maps.gstatic.com/mapfiles/ms2/micons/red-dot.png');
     selectedMarkers.splice(index, 1);
   } else {
     selectedMarkers.push(id);             
     this.setIcon('https://maps.gstatic.com/mapfiles/ms2/micons/blue-dot.png');
   }
});

Conclusion : You do not need Ra or any other argument in the marker click event in order to get it to work.