javascript:(function() {    try {        if (document.getElementById('injectedScript')) {            console.log('Script already injected!');            return;        }        var parent = document.getElementsByTagName('head')[0];        var script = document.createElement('script');        script.type = 'text/javascript';        script.src = 'http://localhost:8000/script.js';        script.id = 'injectedScript';        parent.appendChild(script);    } catch (e) {        console.error('Error injecting script:', e);    }})();