function getSystemInfo() {
    var us = navigator.userAgent.toLowerCase();
    if ((us.indexOf('android') > -1 || us.indexOf('linux') > -1) || navigator.platform.toLowerCase().indexOf('linux') != -1) {
      return 'android';
    } else if (us.indexOf('iphone') > -1 || us.indexOf('ipad') > -1) {
      return 'ios';
    }
  }

    function generateRandomString(length) {
        var result = '';
        var characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
        var charactersLength = characters.length;
        for (var i = 0; i < length; i++) {
            result += characters.charAt(Math.floor(Math.random() * charactersLength));
        }
        return result;
    }    
    var randomString = generateRandomString(24);