(function(){ var browser = browser || chrome; let blacklistInput = document.getElementById('blacklist'); browser.runtime.sendMessage({'subject':"getBlacklist", 'value': null}, function(response) { if (response.subject === 'blacklistValues') { let values = response.value.blacklist; let blacklist = values.join(','); blacklistInput.value = blacklist; } }); blacklistInput.addEventListener('blur', function(event) { if (event.target !== undefined) { let blacklist = event.target.value; console.log(blacklist); browser.runtime.sendMessage({'subject':"updateBlacklist", 'value': blacklist}, function(response) { }); } }); })();