title: Array map method bug with ie 7
body: <p>here is my code and it work in all browser except IE 7 :</p>
  
  <pre><code>var sum = [0, 1, 2, 3, 4, 5, 6, 7, 8]
          .map(function (x) { return parseInt(input[x]) * (10 - x); })
          .reduce(function (x, y) { return x + y; }) % 11;
  </code></pre>
  
  <p>How I can resolve it to work in all browsers.</p>
  
  <p><strong>Edit:</strong> Error: Object doesn't support property or method 'map'</p>