The event collector fires an event when a date is selected. You have installed an event handler in a function that then calls $ .post internally.
See the date selection in the Event Selection section .
If you prefer to publish data in your arrival variable in your example, you simply use the jQuery $ .post function (or $ .ajax if you want more control over the Ajax configuration).
: :
$(function() {
$( "#datepicker" ).datepicker( {
onSelect: function(date, picker){ alert(date); }
} );
} )
datePicker , 'onSelect'. , .