JS проверка Retina и HD дисплея

Как проверить Retina display и high definition display?

Код JS:

function isHighDensity(){/*проверка HD display*/
 return ((window.matchMedia && (window.matchMedia('only screen and (min-resolution: 124dpi), only screen and (min-resolution: 1.3dppx), only screen and (min-resolution: 48.8dpcm)').matches || window.matchMedia('only screen and (-webkit-min-device-pixel-ratio: 1.3), only screen and (-o-min-device-pixel-ratio: 2.6/2), only screen and (min--moz-device-pixel-ratio: 1.3), only screen and (min-device-pixel-ratio: 1.3)').matches)) || (window.devicePixelRatio && window.devicePixelRatio > 1.3));
}

function isRetina(){/*проверка Retina*/
 return ((window.matchMedia && (window.matchMedia('only screen and (min-resolution: 192dpi), only screen and (min-resolution: 2dppx), only screen and (min-resolution: 75.6dpcm)').matches || window.matchMedia('only screen and (-webkit-min-device-pixel-ratio: 2), only screen and (-o-min-device-pixel-ratio: 2/1), only screen and (min--moz-device-pixel-ratio: 2), only screen and (min-device-pixel-ratio: 2)').matches)) || (window.devicePixelRatio && window.devicePixelRatio >= 2)) && /(iPad|iPhone|iPod)/g.test(navigator.userAgent);
}

Использовать так:

if(isHighDensity()){
 console.log('HD display')
}else{
 console.log('NOT HD')
};

if(isRetina()){
 console.log('Retina')
}else{
 console.log('NOT retina')
}

Также можно использовать для проверки HD дисплея:

function is_high_resolution_screen() {
 return window.devicePixelRatio > 1;
}