jQuery improvement

Hey guys, I just had an idea that someone has probably already thought
of but I think it greatly enhance the jQuery library. What if you
could do this...
$('#myDiv').css('height', +=10);
Sort of retrieve and set the new value in one call.
Maybe I'll write it when I get a minute. :) Maybe someone else who
knows the lib better than me could write it more quickly.
Anyway, just an idea