var ext_api = (typeof browser === 'object') ? browser : chrome; window.localStorage.clear(); sessionStorage.clear(); // send domain to background.js (to clear cookies) ext_api.runtime.sendMessage({ domain: document.domain }); let msg = "Cookies (and local storage) removed from " + document.domain; showMessage(msg, 2000); function showMessage(msg, duration) { var el = document.createElement("div"); el.setAttribute("style", "position:fixed;top:40%;left:40%;z-index:99;padding:4px;font-family: Arial, sans-serif;font-size:18px;color:white;background-color:blue;"); el.innerText = msg; setTimeout(function () { el.parentNode.removeChild(el); }, duration); (document.body || document.head || document.documentElement).appendChild(el); }