function save(e) { console.log("OK"); browser.storage.local.set({ username: document.querySelector("#user").value }); browser.storage.local.set({ password: document.querySelector("#passwd").value }); if(document.querySelector("#isMS").checked){ browser.storage.local.set({ msemail: document.querySelector("#msemail").value }); }else { browser.storage.local.set({ msemail: null }); } e.preventDefault(); } function loadCreds() { var storageItem = browser.storage.local.get('username'); storageItem.then((res) => { if(res.username != void(0)) document.forms[0].user.value = res.username; }); storageItem = browser.storage.local.get('password'); storageItem.then((res) => { if(res.password != void(0)) document.forms[0].passwd.value = res.password; }); storageItem = browser.storage.local.get('msemail'); storageItem.then((res) => { if(res.msemail != void(0)){ document.forms[0].msemail.value = res.msemail; document.forms[0].isMS.checked = true; document.getElementById("msemail").style.display = "block"; } }); } document.addEventListener('DOMContentLoaded', loadCreds); document.querySelector("form").addEventListener("submit", save); const checkbox = document.getElementById('isMS') checkbox.addEventListener('change', (event) => { document.getElementById("msemail").style.display = event.currentTarget.checked ? 'block' : 'none'; })