monitorSelections jQuery extension

// Working example: http://www.jsfiddle.net/mUrVB/22/

(function($) {

    $.fn.selection = function() {
        var start = this[0].selectionStart,
              end = this[0].selectionEnd;
    
        if (start === end) {
            return null;
        }
    
        return {
            start: start,
            end: end,
            equals: function(selection) {
                return selection && selection.start === start && selection.end === end;
            }
        };
    };
    
    $.fn.monitorSelection = function() {
        return self = this.bind("keyup mousemove keydown mouseup click", function(event) {
            var lastSelection = self.data("lastSelection");
            var currentSelection = self.selection();

            // If there's a selection and there wasn't one or it has changed
            
            if (currentSelection && (!lastSelection || !currentSelection.equals(lastSelection))) {
                event.type = "onSelected";
                self.trigger(event, [currentSelection.start, currentSelection.end]);
            }
            
            // If there was a selection and now there's not
            
            else if (!currentSelection && lastSelection ) {
                event.type = "onDeselected";
                self.trigger(event);
            }
 
            self.data("lastSelection", currentSelection);
        });
    };

})(jQuery);