lib/Remote/RemoteTargetLocator.php
public function defaultContent()
    {
        $params = ['id' => null];
        $this->executor->execute(DriverCommand::SWITCH_TO_FRAME, $params);

        return $this->driver;
    }
public function defaultContent()
    {
        $params = ['id' => null];
        $this->executor->execute(DriverCommand::SWITCH_TO_FRAME, $params);

        return $this->driver;
    }
public function defaultContent ( ) { $ params = [ 'id' => null ] ; $ this -> executor -> execute ( DriverCommand :: SWITCH_TO_FRAME , $ params ) ; return $ this -> driver ; }
Switch to the main document if the page contains iframes. Otherwise, switch
to the first frame on the page.

@return WebDriver The driver focused on the top window or the first frame.
Switch to the main document if the page contains iframes . Otherwise switch to the first frame on the page .