From the "Updating Chosen Dynamically" section in the docs: You need to trigger the 'chosen:updated' event on the field
$(document).ready(function() {
$('select').chosen();
$('button').click(function() {
$('select').val(2);
$('select').trigger("chosen:updated");
});
});
NOTE: versions prior to 1.0 used the following:
$('select').trigger("liszt:updated");
~ Answered on 2012-01-23 23:40:34