Date picker with disable dates JQuery UI issue - php

Question

I need to update the disabled dates of a UI Jquery datepicker when a different city is chosen from a combo box, so what iv done is onchange of the combo box run the following function which does an ajax call to a php script which hits the DB via sql and returns the dates based on the city whcih i dump into the unavalibledates variable and rerun the .datepicker
This only works the first time its run, after which is does not update, but does not error. how do I make it update.
function update_datepicker()
{
$.ajax({
type: "POST",
url: "scripts/deals.php?val=05&city="+document.getElementById('city_combo').value,
success: function (temp2)
{
var unavailableDates = [eval(temp2)];
function unavailable(date) {
dmy = date.getDate() + "-" + (date.getMonth()+1) + "-" + date.getFullYear();
if ($.inArray(dmy, unavailableDates) == -1) {
return [true, ""];
} else {
return [false,"","Unavailable"];
}
}
$('#datepicker').datepicker({ beforeShowDay: unavailable });
}
});
}

Answer 1

do not create every time a new datepicker, just update your current
var unavailableDates;
function unavailable(date) {
dmy = date.getDate() + "-" + (date.getMonth()+1) + "-" + date.getFullYear();
if ($.inArray(dmy, unavailableDates) == -1) {
return [true, ""];
} else {
return [false,"","Unavailable"];
}
}
var dp = $('#datepicker').datepicker({ beforeShowDay: unavailable });
function update_datepicker()
{
$.ajax({
type: "POST",url: "scripts/deals.php?val=05&city="+$('#city_combo').val(),
success: function (temp2)
{unavailableDates = [eval(temp2)];}
});
}

Answer 2

just add,
$('#datepicker').datepicker( "destroy" );
Before you recreate it, hope this helps otehrs