Question

I have this piece of code in my background.js:

chrome.tabs.onUpdated.addListener(function(tabId, changeInfo, tab) {
    if (changeInfo.status == 'complete') {
        chrome.tabs.executeScript(null, {code:"alert('Loaded');"});
    }
});

This should give me an alert every time a page is loaded, but it doesn’t..

Answer 1

Check the tabs permission on your manifest file. Also use the tabId on executeScript:

chrome.tabs.onUpdated.addListener(function(tabId, changeInfo, tab) {
    if (changeInfo.status == 'complete') {
        chrome.tabs.executeScript(tabId, {code:"alert('Loaded');"});
    }
});

If this doesn’t resolve your problem give me more details.