jQuery Forum

http://tablesorter.com/docs/example-ajax.html
inside the callback (the third argument for .load )
// let the plugin know that we made a update
$("table").trigger("update");

$('#foo').click(function() {
$('#centro').empty();
$('#centro').hide();
$('#centro').fadeIn(3000).load('results_casa_mes.asp',{ nm_mes:
document.getElementById('teste4').value, pessoas:
document.getElementById('pessoas').value, tipo: document.getElementById
('tipo').value, localidade: document.getElementById
('localidade').value });
});
can you help me with that. I'm starting with jquery and i'm not an
experienced programer. Thanks.

$('#foo').click(function() {
$('#centro').empty();
$('#centro').hide();
$('#centro').fadeIn(3000).load('results_casa_mes.asp',{ nm_mes:
document.getElementById('teste4').value, pessoas:
document.getElementById('pessoas').value, tipo: document.getElementById
('tipo').value, localidade: document.getElementById
('localidade').value });
$("table").trigger("update");
});
I've tried this with no luck

You triggered the update before the data loaded, you have to do that
in a function as the third argument:
$('#foo').click(function() {
$('#centro').empty();
$('#centro').hide();
$('#centro').fadeIn(3000).load('results_casa_mes.asp', {
nm_mes: $('#teste4').val(),
pessoas: $('#pessoas').val(),
tipo: $('#tipo').val(),
localidade: $('#localidade').val()
}, function(){ $("table").trigger("update"); } );
});

Please look at http://realferias.com/pager.asp . When the table is in
a file that is loaded, the tablesorter and the pager fails. i?m using
the $("table").trigger("update"); but nothing.

I've had a closer look at that page and triggering the update is only
needed if you're updating just the table contents, I thought you were
doing that. And as you are loading the same page again all the
javascript will be loaded again too, which is unnencessary in this
case, but most likely the main problem is that there will be two
elements with the same id.