1. Introduction
2. What is a Toolbar?
3. How Toolbars Work
4. Why Toolbars are Free
5. Google Toolbar

How Toolbars Work

Understanding how a toolbar functions

Toolbars are written by software developers who have specific knowledge of the application to which the toolbar is attached. They are usually created using the same programming language and tools used to create the application itself. Applications with built-in tool bars can take advantage of any and all of the application's functionality.

The truly interesting toolbars, however, are those that are developed by others to extend the functionality of an application. Most browser tool bars fall into this category, for example. You can refer to such toolbars as extension toolbars as opposed to built-in toolbars.

Applications must be specifically designed to support extension via tool bars. The developer of the application must expose a facility that lets other developers "hook into" the application using what is commonly referred to as an application programming interface, or API for short. Besides providing for the ability to create and manipulate toolbars, the API must also expose some part of the application's core functionality so that the tool bar can do something when the user presses a toolbar button. For example, a browser would expose a way for a toolbar to load a new web page.

Installing a toolbar usually means downloading executable code that effectively grafts itself onto the application. As you can imagine, then, there are important security issues to consider before downloading and installing a toolbar, because once installed, the toolbar has unfettered access to your machine. You should only install toolbars from reputable sources.