[jQuery] Update element when changes

[ReynierPM]

Hi every:
I have two input fields and I want the second updated every time I 
change a value in the first. I wrote this function but it doesn't work 
until the first element lost focus (for example I clic anywhere or press 
TAB button)

$('#order').change(function(){
    $('#total_buyed').val($(this).val() * 2.75);
});

What I'm doing wrong
--
Saludos
ReynierPM