How to get event page from content script?

Question

What's the preferred way to get the eventPage from a content script? The old method (chrome.extension.getBackgroundPage) has been replaced with chrome.runtime.getBackgroundPage, but the chrome.runtime API is not accessible from content scripts.

Answer 1

The chrome.extension.getBackgroundPage method is to access the background page from a browser action page. To access the background/event-page js, the below code should work from a content script:

 chrome.runtime.sendMessage({greeting: "hello"}, function(response) {
   console.log(response.farewell);
 });

In the background-page/event page JS you have to setup a listener to listen for requests from content scripts:

chrome.runtime.onMessage.addListener(
 function(request, sender, sendResponse) {
    console.log(sender.tab ?
            "from a content script:" + sender.tab.url :
            "from the extension");
    if (request.greeting == "hello")
        sendResponse({farewell: "goodbye"});
});

Hope this helps. chrome.runtime.getBackgroundPage from content script will never work; you can only send messages to it(like above).