Access page opened in new window

[cosinus90]

Hello,

There's a page where I click on an element and Javascript opens new page in new window. How to access it?
With the help of ChatGPT I have this code

    function openChart() {
        try {
            $session = $this->page->getSession();
            $discoverTargetsMessage = new Message('Target.setDiscoverTargets', ['discover' => true]);
            $session->sendMessage($discoverTargetsMessage);

            $this->js('document.querySelector("a[class^=goToChartButton]").click()'); // click here
            $targets = $this->browser->getTargets();


            $newTarget = null;
            foreach ($targets as $target) {
                $targetType = $target->getTargetInfo('type');
                $targetId = $target->getTargetInfo('targetId');
                if ($targetType === 'page' && $targetId !== $this->page->getSession()->getTargetId()) {
                    $newTarget = $target;
                    break;
                }
            }



            if ($newTarget) {
                $session = $this->browser->getConnection()->createSession($targetId);


        
                // waiting for page loaded
                $session->on('Page.loadEventFired', function () use ($session) {
                    $response = $session->sendMessageSync(new Message('Runtime.evaluate', [
                        'expression' => 'document.documentElement.outerHTML'
                    ]));
                    echo $response['result']['value']; 
                });
            } else {
                echo "Error opening chart page\n";
            }

        } 
    }

The problem is that
Uncaught HeadlessChromium\Exception\CommunicationException: Message could not be sent. Reason: the connection is closed.

How to fix this? And, if it possible, I would prefer to substitute $this->page so that I could use it outside of the function later.