Microsoft Active Accessibility

Microsoft Active Accessibility (MSAA) is an Application Programming Interface (API) for user interface accessibility. MSAA was introduced as a platform add-on to Microsoft Windows 95 in 1997. MSAA is designed to help Assistive Technology (AT) products interact with standard and custom user interface (UI) elements of an application (or the operating system), as well as to access, identify, and manipulate an application's UI elements. AT products work with MSAA enabled applications in order to provide better access for individuals who have physical or cognitive difficulties, impairments, or disabilities. Some examples of AT products are screen readers for users with limited sight, on screen keyboards for users with limited physical access, or narrators for users with limited hearing. MSAA can also be used for automated testing tools, and computer-based training applications.

The current and latest specification of MSAA is found in part of Microsoft UI Automation Community Promise Specification.

Active Accessibility was initially referred to as OLE Accessibility and this heritage is reflected in the naming of its binary components such as oleacc.dll and the header file oleacc.h which contains definitions and declarations. As part of Microsoft's ActiveX branding push in March 1996, OLE Accessibility was renamed ActiveX Accessibility (sometimes referred to as AXA) and presented as such at the Microsoft Professional Developers Conference in San Francisco, March 1996. Later, the ActiveX branding was reserved for internet-specific technologies, and ActiveX Accessibility became Active Accessibility and frequently shortened to MSAA.

MSAA was originally made available in April 1997 as part of the Microsoft Active Accessibility Software Developers Kit (SDK) version 1.0. The SDK packaged included documentation, programming libraries, sample source code, and a Re-Distributable Kit (RDK) for accessible technology vendors to include with their products. The RDK included updated operating system components for Microsoft Windows 95. Since Windows 98 and Windows NT 4.0 Service Pack 4, MSAA has been built-into all versions of the Windows platform, and has received periodic upgrades and patches over time.

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