text: function generateMixed(n) {
      var chars = ['0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'];
       var res = "";
       for(var i = 0; i < n ; i ++) {
           var id = Math.ceil(Math.random()*35);
           res += chars[id];
       }
       return res;
  }
  