The nsITextScroll is an interface that can be implemented by a control that
 supports text scrolling. 
[scriptable, uuid(067b28a0-877f-11d3-af7e-00a024ffc08c)]
interface nsITextScroll : nsISupports

Methods

 Scroll the view up or down by aNumLines lines. positive
 values move down in the view. Prevents scrolling off the
 end of the view.
 @param numLines number of lines to scroll the view by
void scrollByLines(in long numLines)
 Scroll the view up or down by numPages pages. a page
 is considered to be the amount displayed by the clip view.
 positive values move down in the view. Prevents scrolling
 off the end of the view.
 @param numPages number of pages to scroll the view by
void scrollByPages(in long numPages)