Usage of nsISelection Interface

 Method for accessing this window's selection object.

nsISelection getSelection()

 GetSelection will return the selection that the presentation
  shell may implement.

 @param aType will hold the type of selection //SelectionType
 @param _return will hold the return value

nsISelection getSelection(in short type)

  If the selection is set to a non-null value, then the
  selection is used for encoding, otherwise the entire
  document is encoded.
 @param aSelection The selection to encode.

void setSelection(in nsISelection aSelection)

 Start a modal drag session using the selection as the drag image.
 The aDragEvent must be supplied as the current screen coordinates of the
 event are needed to calculate the image location.

void invokeDragSessionWithSelection(in nsISelection aSelection, in nsISupportsArray aTransferableArray, in unsigned long aActionType, in nsIDOMDragEvent aDragEvent, in nsIDOMDataTransfer aDataTransfer)

 
 Called after the editor deletes the selection.
 @param aSelection   The selection, after deletion

void DidDeleteSelection(in nsISelection aSelection)

 
 Called before the editor deletes the selection.
 @param aSelection   The selection to be deleted

void WillDeleteSelection(in nsISelection aSelection)

 Checks if the anonymous nodes created by the HTML editor have to be
 refreshed or hidden depending on a possible new state of the selection
 @param aSelection [IN] a selection

void checkSelectionStateForAnonymousButtons(in nsISelection aSelection)