JQuery - Events binding and cached elements

Question

Having some code like this one

$a = $('#a');
$b = $('#b');
$c = $('#c');

$('#a, #b, #c').keyup(function () {
    //Event handling
});

I would like to know

1. If it is possible to use existing cached elements to handle events instead of the selector.
2. If this is possible and proper, does it make any difference?

Answer 1

Of course, using cached elements is better for performance. If you want to bind a function on multiple cached elements, you can use .add() :

$a.add($b).add($c).keyup(function(){});