chrome.runtime.onMessage.addListener( function(request, sender, sendResponse) { console.log("Message from content: " + request); var messages = { 'error': 'Error parsing RDF', 'unlicensed': 'No machine readable licensing', 'licensed': 'License declared' }; chrome.pageAction.setTitle({ tabId: sender.tab.id, title: messages[request.check] }); var icon = { 'error': 'red', 'unlicensed': 'amber', 'licensed': 'green' }; chrome.pageAction.show(sender.tab.id); chrome.pageAction.setIcon({ tabId: sender.tab.id, path: 'pageIcon-' + icon[request.check] + '.png' }); sendResponse({text: "ok"}); } );