About add-ins
Add-ins are supplemental programs that extend the capabilities of Microsoft FrontPage by adding custom commands and specialized features. You can obtain add-ins from the Microsoft Office Online Web site, third-party vendors, or you can write your own custom add-in programs by using Microsoft Visual Basic for Applications.
To conserve memory and increase the speed of FrontPage, it's a good idea to unload add-in programs you don't use often. When you unload an add-in, its features and commands are removed from FrontPage, but the add-in file itself remains on your computer for easy reloading.
Developers can use Component Object Model (COM) add-ins, which provide additional functionality in a variety of programming languages, including Microsoft Visual Basic, Microsoft Visual C++, and Microsoft Visual J++. As a developer, you'll find information about designing COM add-ins in Visual Basic Help. While you are developing and testing, you can load or unload a COM add-in in FrontPage before you have a working installation program for your add-in.
Note Do not confuse add-ins with plug-ins. A plug-in is one of a set of software modules that integrate into Web browsers to offer a range of interactive and multimedia capabilities.
Security Security vulnerabilities in external files or controls may extend to Web pages that use those items. For example, external style sheets (files with a .css extension), script files (files with a .js extension), custom ASP.NET controls, or other items, may pose a security risk. Be sure your style sheets, add-ins, themes, executables, scripts, controls, or other files come from trusted sources.