jQuery event object removes rangeParent & rangeOffset under Firefox

jQuery event object removes rangeParent & rangeOffset under Firefox

Firefox adds two very useful properties to its native event object: on mouse events: rangeParent & rangeOffset.

However, when I use jQuery to bind my handlers (under Firefox), these two properties are not present on the jQuery event object. How can I access these Firefox specific properties? Get a reference to the native Firefox event object?

$(selector).mousedown(function (event) {
   . ....
    // How can I access rangeParent & rangeOffset from this context in Firefox?

});

Thanks for your help