Cambiar el valor de desplegable usando jQuery
$('#ddlID').val('New_OptionValue').change()
Inexpensive Iguana
$('#ddlID').val('New_OptionValue').change()$('select[name^="salesrep"] option[value="Bruce Jones"]').attr("selected","selected");$("#comboboxid").val(yourvalue).trigger("chosen:updated");
$('select[name^="salesrep"] option:selected').attr("selected",null);