map.on('click') coordinates wrong in Firefox - openlayers-3

Question

I am using OpenLayers 3.10.1 and the following code:
map.on('click', function (map, evt) {
var mouseCoords = [evt.originalEvent.offsetX, evt.originalEvent.offsetY];
alert(mouseCoords);
});
When I click as near as I can to the upper left corner of the map in IE or Chrome, I get an alert with the mouse coordinates offset from the top left corner of the map div, i.e. something sensible like [3,4].
But when I try the same things I get the mouse coordinates relative to the browser window and not the map div. Does anyone know why this is? Am I using an outdated way to find the mouse coordinates (ultimately so I can calculate which feature was clicked)?

Answer 1

Some alternatives:
map.on('click', function(evt){
console.info(evt.pixel);
console.info(map.getPixelFromCoordinate(evt.coordinate));
});

Answer 2

The following code works for me (openlayer 4.4, angular 4+)
_initMap() {
console.info("_initMap");
this.mapW = new ol.Map({
layers: [
new ol.layer.Tile({
source: new ol.source.OSM()
})
],
target: 'myMapDiv',
controls: ol.control.defaults({
attributionOptions: /** #type {olx.control.AttributionOptions} */ ({
collapsible: false
})
}),
view: new ol.View({
center: ol.proj.fromLonLat([this.lon, this.lat]);,
zoom: 12
})
});
const theMap = this.mapW;
// display on click
this.mapW.on('click', function(evt) {
/* // you want to detect feature click
var feature = theMap.forEachFeatureAtPixel(evt.pixel,
function(feature, layer) {
return feature;
});
if (feature) {
var fname = feature.getProperties().name;
console.info("feature clicked:" + fname);
return;
}
*/
console.info(evt.coordinate);
console.info(ol.proj.toLonLat(evt.coordinate)); // <=== coordinate projection
});
JS console results (when clicking close to Grenoble in France):
(2) [637000.3050167585, 5652336.68427412]
(2) [5.722271099853512, 45.19540527485873]