// Production steps of ECMA-262, Edition 5, 15.4.4.14 // Reference: es5.github.io/#x15.4.4.14 if (!Array.prototype.indexOf) {

Array.prototype.indexOf = function(searchElement, fromIndex) {

  var k;

  // 1. Let O be the result of calling ToObject passing
  //    the this value as the argument.
  if (this == null) {
    throw new TypeError('"this" is null or not defined');
  }

  var O = Object(this);

  // 2. Let lenValue be the result of calling the Get
  //    internal method of O with the argument "length".
  // 3. Let len be ToUint32(lenValue).
  var len = O.length >>> 0;

  // 4. If len is 0, return -1.
  if (len === 0) {
    return -1;
  }

  // 5. If argument fromIndex was passed let n be
  //    ToInteger(fromIndex); else let n be 0.
  var n = +fromIndex || 0;

  if (Math.abs(n) === Infinity) {
    n = 0;
  }

  // 6. If n >= len, return -1.
  if (n >= len) {
    return -1;
  }

  // 7. If n >= 0, then Let k be n.
  // 8. Else, n<0, Let k be len - abs(n).
  //    If k is less than 0, then let k be 0.
  k = Math.max(n >= 0 ? n : len - Math.abs(n), 0);

  // 9. Repeat, while k < len
  while (k < len) {
    // a. Let Pk be ToString(k).
    //   This is implicit for LHS operands of the in operator
    // b. Let kPresent be the result of calling the
    //    HasProperty internal method of O with argument Pk.
    //   This step can be combined with c
    // c. If kPresent is true, then
    //    i.  Let elementK be the result of calling the Get
    //        internal method of O with the argument ToString(k).
    //   ii.  Let same be the result of applying the
    //        Strict Equality Comparison Algorithm to
    //        searchElement and elementK.
    //  iii.  If same is true, return k.
    if (k in O && O[k] === searchElement) {
      return k;
    }
    k++;
  }
  return -1;
};

}