标签对象在chrome扩展名中未定义

Question

I am adding a simple listener to a tab that shows the page action in a chrome extension, but each time, tab.id is undefined. This script runs in a background page:

chrome.tabs.onUpdated.addListener
(
    function(tab)
    {

        chrome.pageAction.show(tab.id);

    }
);

Each time, I get the error message that tab.id is undefined. Why is this happening? I have tabs in my permissions file:

"permissions":
    [
        "tabs"
    ]

The weirder part is that it works fine in the onCreated version when I add a listener, but the two functions are exactly the same:

chrome.tabs.onCreated.addListener
(
    function(tab)
    {
            chrome.pageAction.show(tab.id);
            concole.log("added onCreated listener");
    }
);

That works fine. What could be causing this?

Answer 1

According to the documenation for chrome.tabs.onUpdated :

The callback parameter should specify a function that looks like this:

function(integer tabId, object changeInfo, Tab tab) {...};