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
  }
  
  // Detect User Agents
  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')
  
  // Detect Touch Devices
  if ('createTouch' in document) flag('touch')
  if (window.navigator.msPointerEnabled) flag('mspointer')
  if (window.navigator.msPointerEnabled && window.navigator.msMaxTouchPoints) flag('touch')
  
  // Detect Fullscreen / App Mode
  if ( ('standalone' in window.navigator) && window.navigator.standalone) 
    flag('standalone')
  
  // Detect Retina Displays
  if (window.devicePixelRatio >= 2) flag('retina')
  
  // Detect iframes
  if (window !== window.top) flag('embedded')
  
  return flags
}()