code: function isIOS () {
          if ( _isIOS === undefined ) _isIOS = (/iPad|iPhone|iPod/g).test( navigator.userAgent );
          return _isIOS;
      }
docs: Detects if the browser is on iOS. Works for Safari as well as other browsers, say, Chrome on iOS.
  
  Required for some iOS behaviour which can't be feature-detected in any way.
  
  @returns {boolean}