Takes a string in format "param1=value1&param2=value2" and returns an javascript object. The opposite of https://api.jquery.com/serialize

unserialize.js

/**
 * $.unserialize
 *
 * Takes a string in format "param1=value1&param2=value2" and returns an object { param1: 'value1', param2: 'value2' }. If the "param1" ends with "[]" the param is treated as an array.
 *
 * Example:
 *
 * Input:  param1=value1&param2=value2
 * Return: { param1 : value1, param2: value2 }
 *
 * Input:  param1[]=value1&param1[]=value2
 * Return: { param1: [ value1, value2 ] }
 *
 * @todo Support params like "param1[name]=value1" (should return { param1: { name: value1 } })
 * Usage example: console.log(unserialize("one="+escape("& = ?")+"&two="+escape("value1")+"&two="+escape("value2")+"&three[]="+escape("value1")+"&three[]="+escape("value2")));
 */
unserialize = function(serializedString) {
  var str = decodeURI(serializedString),
      pairs = str.split('&'),
      obj = {}, p, idx;

  for (var i=0, n=pairs.length; i < n; i++)
  {
    p = pairs[i].split('=');
    idx = p[0];
    if (obj[idx] === undefined)
    {
      obj[idx] = unescape(p[1]).replace(/\+/g, ' ');
    }
    else
    {
      if (typeof obj[idx] == "string")
      {
        obj[idx]=[obj[idx]];
      }
      obj[idx].push(unescape(p[1]).replace(/\+/g, ' '));
    }
  }
  return obj;
};

Does this jQuery function do exactly the same as this js function?
https://github.com/kvz/phpjs/blob/master/functions/var/unserialize.js