const IS_FIREFOX = (typeof chrome === "undefined"); const IS_CHROME = (typeof browser === "undefined"); let init = async () => { let backendInput = document.getElementById("backend"); let saveButton = document.getElementById("saveButton"); if (IS_FIREFOX) backendInput.value = (await browser.storage.local.get("backend")).backend; if (IS_CHROME) backendInput.value = await new Promise(resolve => { chrome.storage.local.get("backend", result => { resolve(result.backend); }) }); saveButton.onclick = () => { const setLocalObject = { backend: backendInput.value }; if (IS_FIREFOX) browser.storage.local.set(setLocalObject); if (IS_CHROME) chrome.storage.local.set(setLocalObject); } } init();