Chrome Event Logger

CEL, the Chrome Event Logger, logs all Chrome browser API events to the console of its background page. It is intended to help developers see the names of events Chrome is triggering, when they occur, and with what arguments. Typical use cases are:

1. You wonder if there is a Chrome API event that's triggered for some action you take in the browser. Rather than guessing what the event might be and trying to find it in the API docs, you can enable CEL, perform the action in Chrome, and see what CEL logs.

2. You're writing an extension and are unsure about whether an event is being triggered or with what arguments. Instead of adding an event listener in your own code and reloading your extension, you can just look in the CEL log.

## Viewing the logging

Once installed, you can examine the CEL logging by visiting chrome://extensions, clicking to enable Developer mode, and then clicking the link next to the CEL icon where it says Inspect views: _generated_background_page.html

## Manually adjusting logging

In the JS console for the extension's background page, there are several commands you can run to adjust what is logged:

// Return a list of the chrome.* API events being logged.
CEL.enabled()

// Return a list of the chrome.* API events being ignored.
CEL.disabled()

// Enable logging of some calls (see below).
CEL.enable(name1, name2, ...)

// Disable logging of some calls (see below).
CEL.disable(name1, name2, ...)

The names you pass to CEL.enable and CEL.disable can be individual API calls (without the leading "chrome."), or can be higher-level categories. Here are some examples:

// Enable chrome.tabs.onCreated and all chrome.webRequest.* events:
CEL.enable('tabs.onCreated', 'webRequest')

// Disable all chrome.tabs.* events and chrome.webNavigation.onCommitted
CEL.disable('tabs', 'webNavigation.onCommitted')

Note that CEL.enable will enable all necessary higher level logging. So, for example, if you call CEL.enable('omnibox.onInputEntered') all chrome.omnibox.* events (that have not been explicitly disabled) will be logged. If you don't want to enable and disable groups of calls in this way, always pass explicit API calls.

CEL.disabled will show you the names of individual calls that are disabled, as well as any disabled higher levels.

## Global enable / disable

The extension provides a context menu item that lets you globally enable or disable logging.