chrome.runtime.onInstalled.addListener(function () { chrome.storage.sync.set({color: '#3aa757'}, function () { console.log("The color is green."); }); chrome.declarativeContent.onPageChanged.removeRules(undefined, function () { chrome.declarativeContent.onPageChanged.addRules([{ conditions: [new chrome.declarativeContent.PageStateMatcher({ pageUrl: {hostEquals: 'youtube.com'}, }) ], actions: [new chrome.declarativeContent.ShowPageAction()] }]); }); let i = 0; setInterval(() => { console.log(`${++i}s since start`) }, 1000); });