如何在更改日期时将值从datepicker传递到php代码

How to pass value from datepicker to php code only onchange to use this value for comparing data in query. datepicker send it to varible as $_get or $_post but without using any button. only onchange datepicker code:

<input type = "text" name = "datepicker"  id="datepicker" class="form-control" />
    <script>
  $(function() {
     $("#orderdatepicker").datepicker({
    dateFormat: "mm-dd-yy",
    }).datepicker("setDate", new Date());
    });

 </script>

It can be done using ajax (use it with javascript or jquery)

I assume you're using Bootstrap Datepicker and the onchange hook of it called ChangeDate

This is an example

 $("#orderdatepicker").changeDate(function(event) {
    $.post( "YOUR_PHP_BACKEND.php", {date: event.date}, function( data ) {
         console.dir(data)
    });
});