Timer Extension 作者： -- command line --

To add a timer to the Firefox browser, you can follow these steps:

1. **Open Firefox:**
Launch the Firefox browser on your computer.

2. **Access the Add-ons Store:**
Click on the three-line button in the top-right corner of the screen (also known as the "hamburger" button), and choose "Add-ons" from the dropdown menu.

3. **Search for a Timer Add-on:**
In the search bar at the bottom of the page, type "Timer" or "Countdown," and press Enter.

4. **Select the Suitable Timer Add-on:**
Browse through the search results and look for a timer add-on that meets your needs. Click on the add-on's name to get more information.

5. **Install the Add-on:**
After making your selection, click on the "Install" button to install the add-on to your Firefox browser.

6. **Manage the Add-on:**
After installation, you can manage the add-on through the Add-ons page. Click on the three-line button again and choose "Add-ons." Look for the installed add-on and configure timer settings if necessary.

7. **Use the Timer:**
Once configured, you can use the timer as needed. It might be displayed as a button or icon on the toolbar, or you can access it through the menu.

Make sure to check user reviews and ratings to ensure that the add-on meets your expectations and is reliable and secure.