if (!Array.prototype.indexOf)    Array.prototype.indexOf = function (elt /*, from*/) {      var len = this.length >>> 0;      var from = Number(arguments[1]) || 0;      from = (from < 0)          ? Math.ceil(from)          : Math.floor(from);      if (from < 0)        from += len;      for (; from < len; from++) {        if (from in this &&            this[from] === elt)          return from;      }      return -1;    };