Excluding several layers from forEachFeatureAtPixel function using OpenLayers 3?

Question

I have a map with some vector layers that deliver popups when the user clicks on the markers. I use a forEachFeatureAtPixel function to identify these layers. However, there are also several background layers which should do nothing if you click on them. After looking through this forum for methods, I am able to exclude one layer from the function, but how would I exclude several layers?

Background1 and background2 are the layers that should not deliver any popups. My code is like this:

var background1 = new ol.layer.Vector...

var background2 = new ol.layer.Vector...

var feature = map.forEachFeatureAtPixel(evt.pixel, function(feature, layer) {
if (layer != background1) return feature;
});

if (feature) {

//etc.

That works fine, but I also want to exclude background2. I thought I could write "if (layer != background1 || background2) return feature;" but that doesn't work. What should I do?

Answer 1

if (layer != background1 && layer != background2)