From https://github.com/Element-34/php-webdriver/blob/master/PHPWebDriver/WebDriverActionChains.php#L74

gistfile1.php

  public function moveToElement($toElement, $curl_opts = array()) {
    $this->actions[] = '$this->session->moveto(array("element" => "' . $toElement->getID() . '"), ' . unwind_associated_array($curl_opts) . ');';
    return $this;
  }