} while (--n); 
} 
  indexOf: function(x) {    var index = null, n = this.elements.length, k = n, i;    do { i = k - n;      if (index === null && this.elements[i] == x) {        index = i + 1;      }    } while (--n);    return index;  },
3123	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/3123/5bb35ddb3516d7e68f3747d86540ffaa68de3fe3/vector.js/buggy/src/vector.js