detect.js

device = function(){
  var flags = {}, ua = navigator.userAgent, el = document.createElement('div'), root = document.documentElement, i
  function flag(names) {
    root.className += (root.className ? ' ' : '') + names
    names = names.split(' ')
    for (i = 0; i < names.length; i++) flags[names[i]] = true
  }
  if (ua.indexOf('WebKit/') > -1) flag('webkit')
  if (ua.indexOf('MSIE ') > -1) flag('msie')
  if (ua.indexOf('Firefox') > -1) flag('firefox')
  if (ua.indexOf('(iPad') > -1) flag('ios ipad')
  if (ua.indexOf('(iPhone') > -1 || ua.indexOf('(iPod') > 1) flag('ios iphone')
  if (!flags.ios) flag('desktop')
  el.setAttribute('ontouchstart', 'return;')
  if (typeof el.ontouchstart === 'function') flag('touch')
  if (window.navigator.msPointerEnabled) flag('touch mspointer')
  if (window.navigator.standalone) flag('standalone')
  if (window.devicePixelRatio >= 2) flag('retina')
  if (window !== window.top) flag('embedded')
  return flags
}()