I am using the following script to fire a function depending on whether youre on desktop or mobile. The problem is with retina devices the desktop function is being fired as i guess its pixel ratio is a lot higher. Is there a bullet proof way to get the screens actual pixel size?
var checkWidth = function() {
   if (screen.width >= 1240){
     desktop();
   } else {
     mobile();
   }
};
 
     
    