Web Part Page Services Component (WPSC) Object Model
The WPSC is structured as an object model for ease of programming. Following is a simple diagram of the WPSC object model.
You can write code against the WPSC to support deeper integration of Web Parts or to manipulate your Web Part Page. For example, you can build applications composed of related Web Parts that respond to events in other Web Parts or change titles and captions at run time. You can also think of WPSC as a set of services where each service describes a type of functionality that Web Parts need. For more information about this set of services, see WPSC Services.
The WPSC is part of the SharePoint Foundation Web Part infrastructure. The component is installed with the Web Part infrastructure when you install Windows SharePoint Services. At run time, the infrastructure embeds a WPSC instance on a Web Part Page, where it provides key services at the Web Part and Web Part Page levels.
The WPSC is available as two Microsoft JScript files—one that supports Internet Explorer 5.0, and another that supports Internet Explorer 5.5 and later. At run time, the Web Part infrastructure detects the browser type and provides the appropriate version during Web Part Page rendering.