var default_preferences = {"pkdbf2_level": 1000, "account_url": "https://gpass-demo.soutade.fr/demo"}; function save() { var account_url = document.getElementById('account_url').value; var pkdbf2 = document.getElementById('pkdbf2').value; chrome.storage.local.set({ 'account_url': account_url, 'pkdbf2': pkdbf2, }, function() { alert('Saved'); }); } chrome.storage.local.get(null, function(prefs) { if (!prefs.hasOwnProperty("account_url")) account_url = default_preferences['account_url']; else account_url = prefs['account_url']; if (!prefs.hasOwnProperty("pkdbf2_level")) pkdbf2 = default_preferences['pkdbf2_level']; else pkdbf2 = prefs['pkdbf2_level']; document.getElementById('account_url').value = account_url; document.getElementById('pkdbf2').value = pkdbf2; }); document.getElementById('save').addEventListener("click", save);