function ob_get_flush () {
  // http://kevin.vanzonneveld.net
  // +   original by: Brett Zamir (http://brett-zamir.me)
  // *     example 1: ob_get_flush();
  // *     returns 1: 'some buffer contents'

  var PHP_OUTPUT_HANDLER_START = 1,
    PHP_OUTPUT_HANDLER_END = 4;
  this.php_js = this.php_js || {};
  var phpjs = this.php_js,
    obs = phpjs.obs;
  if (!obs || !obs.length) {
    return false;
  }
  var flags = 0,
    ob = obs[obs.length - 1],
    buffer = ob.buffer;
  if (ob.callback) {
    if (!ob.status) {
      flags |= PHP_OUTPUT_HANDLER_START;
    }
    flags |= PHP_OUTPUT_HANDLER_END;
    ob.status = 2;
    buffer = ob.callback(buffer, flags);
  }
  obs.pop();
  if (obs.length) {
    ob = obs[obs.length - 1];
    ob.buffer += buffer;
  } else {
    this.echo(buffer);
  }
  return buffer;
}

ob_get_flush();

'some buffer contents'