JavaScript - parse XmlHttpRequest.getAllResponseHeaders into a key value pair.

parseheaders.js

/**
 * XmlHttpRequest's getAllResponseHeaders() method returns a string of response
 * headers according to the format described here:
 * http://www.w3.org/TR/XMLHttpRequest/#the-getallresponseheaders-method
 * This method parses that string into a user-friendly key/value pair object.
 */
function parseResponseHeaders(headerStr) {
  var headers = {};
  if (!headerStr) {
    return headers;
  }
  var headerPairs = headerStr.split('\u000d\u000a');
  for (var i = 0, len = headerPairs.length; i < len; i++) {
    var headerPair = headerPairs[i];
    var index = headerPair.indexOf('\u003a\u0020');
    if (index > 0) {
      var key = headerPair.substring(0, index);
      var val = headerPair.substring(index + 2);
      headers[key] = val;
    }
  }
  return headers;
}