Scriptlets
Scriptlets were a technology Microsoft introduced back in IE 4 as a way for developers to create reusable components (this has since been supplanted by behaviors introduced in IE 5.0).
Behaviors are basically complete HTML pages which have implement a special function (called CreateScriptlet) were the developer can expose custom methods and properties of the scriptlet. Scriptlets also let the developer easily create context menus (something not easily done in general back in the IE 4 days). The OBJECT element was used to place the scriptlet on the page. For example:
<object id="oScroller" data="scroller.html" type="text/x-scriptlet" style="height: 200px; width: 200px;"></object>For their day, scriptlets were a great way of creating reusable components in IE. In fact, they can still be very useful if you need to create a component that still needs to be compatible with IE 4. Unfortunately, since Microsoft has started pushing behaviors as the method of choice to create reusable components, it seems that the documentation for scriptlets on MSDN has somehow been misplaced. So here is a page on MSDN that seems to have links to all the relevant pages on how to design and implement scriptlets.