The Tab row enables you to simultaneously keep multiple web pages open in one browser window.

HTML structure:

The Tab row
- Introduction
- Functionality

Introduction:
The Tab row is a feature in web browsers that allows users to open multiple web pages within a single browser window. It appears as a row of tabs at the top of the browser window, just below the address bar.

Functionality:
1. Opening new tabs: One of the main functions of the Tab row is to enable users to open new tabs. By clicking on the "+" or the "New Tab" button, a new tab is opened, and users can enter a URL or search for information in the search bar within that tab.

2. Switching between tabs: With the Tab row, users can easily switch between different open tabs. Each tab represents a separate web page or website, and users can simply click on a tab to bring that page to the forefront of the browser window. This allows for efficient multitasking and quick access to different websites or web pages.

3. Managing tabs: The Tab row also provides options for managing tabs. Users can rearrange the order of tabs by dragging and dropping them into a different position within the Tab row. Additionally, users can close individual tabs by clicking on the "x" button on the tab or by using keyboard shortcuts.

4. Tab customization: Some browsers also offer customization options for the Tab row. Users can pin tabs, which keeps them open and easily accessible even when opening new tabs. They can also group tabs together, allowing for better organization and easier navigation when multiple tabs are open.

Overall, the Tab row is a convenient feature in web browsers that enhances productivity and user experience by enabling the simultaneous opening and management of multiple web pages within a single browser window.