Retina/High Resolution Javascript Check

gistfile1.js

// retina/high resolution check
var retina = function(){

  if(window.devicePixelRatio){
    if(window.devicePixelRatio >= 2){
      return true;
    }
  } else if(window.matchMedia){
    if (window.matchMedia('(min-resolution: 192dpi)').matches){
      return true;
    }
  } else {
    return false;
  }

};