update panel , add function that works after updating

update panel , add function that works after updating

I use jquery datepicker
I have input in the updatePanel
<input id="DateMask" type="text" />
and js code:
function SetD() {
alert(1);
}
$(document).ready(function () {
SetD();
$("#datepicker").datepicker({ changeMonth: true, changeYear: true }); });
But the problem is that when i post my form to the server i only refresh
update panel so $(document).ready(function () doesn't work after
refreshing ,so where i can execute my function from?