As wscourge has implied, chrome.tabs.query()
is a Chrome extension API, which is only available to extensions, not web page JavaScript. In fact, it is only available in the background context of an extension (i.e. not content scripts).
To find the number of tabs that are open, you could do something like:
chrome.tabs.query({windowType:'normal'}, function(tabs) {
console.log('Number of open tabs in all normal browser windows:',tabs.length);
});
If you want to run this from a console, you will need to have an extension loaded that has a background page. You will then need to open the console for the background page. From that console, you can execute the above code.
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