map.on('pointermove',function(e){

                 var pixel = map.getEventPixel(e.originalEvent);

                 var hit = map.hasFeatureAtPixel(pixel);

                 if(hit){

                     map.getTargetElement().style.cursor = 'pointer';

                 }

                 else{

                     map.getTargetElement().style.cursor = '';

                 }

            });