CODE EXAMPLE FOR JAVASCRIPT

detect device ios or android javascript

function getOS() {
  var uA = navigator.userAgent || navigator.vendor || window.opera;
  if ((/iPad|iPhone|iPod/.test(uA) && !window.MSStream) || (uA.includes('Mac') && 'ontouchend' in document)) return 'iOS';

  var i, os = ['Windows', 'Android', 'Unix', 'Mac', 'Linux', 'BlackBerry'];
  for (i = 0; i < os.length; i++) if (new RegExp(os[i],'i').test(uA)) return os[i];
}