browser feature detection

feature-detection.js

// Screen orientation:

if (typeof screen.orientation !== 'undefined') {
    data.orientation = screen.orientation.angle;
} else if (typeof window.orientation !== 'undefined') {
    data.orientation = window.orientation;
}
 
// screen width/height

data.screenW = Math.max(screen.width || 0);
data.screenH = Math.max(screen.height || 0);
// edge case for older Android Browsers that report screen width/height in actual pixels, not CSS px
if (data.ua.indexOf('Android') > -1 && data.ua.indexOf('Chrome') === -1 && data.screenW >= 480 && data.screenH >= 480) {
  data.screenW = data.screenW/2;
  data.screenH = data.screenW/2;
}

// dppx

if (typeof window.devicePixelRatio !== 'undefined') {
  data.dppx = window.devicePixelRatio.toFixed(2);
} else {
  for(var i=5; i>=1; i = (i-0.05).toFixed(2)) {
    if (window.matchMedia("(-webkit-min-device-pixel-ratio: " + i + ")").matches || window.matchMedia("(min-resolution: " + i + "dppx)").matches) {
      data.dppx = i;
      break;
    }
  }
}

// force touch

data.forceTouch = false;
if ('webkitmouseforcedown' in document) {
  data.forceTouch = true;
}

// wide gamut color

data.wideGamut = false;
if (window.matchMedia("(color-gamut: p3)").matches) {
  data.wideGamut = true;
}


// pointer events

data.pointerEvents = false;
if ('PointerEvent' in window || (window.navigator && 'msPointerEnabled' in window.navigator)) {
  data.pointerEvents = true;
}

// touch events

data.touchEvents = false;
if ('ontouchstart' in document || (window.navigator && window.navigator.maxTouchPoints)) {
  data.touchEvents = true;
}