<script type="text/javascript">
        $('#date').datepicker({
          format: "M yyyy",
          startView: 1,
          locale:"ru",
          minViewMode: 1,
          maxViewMode: 2,
          multidate: true,
          multidateSeparator: "-",
          autoClose:true,
        }).on("changeDate",function(event){
          var dates = event.dates, elem=$('#date');
          if(elem.data("selecteddates")==dates.join(",")) return; //To prevernt recursive call, that lead to lead the maximum stack in the browser.
          if(dates.length>2) dates=dates.splice(dates.length-1);
          dates.sort(function(a,b){return new Date(a).getTime()-new Date(b).getTime()});
          elem.data("selecteddates",dates.join(",")).datepicker('setDates',dates);
        });

        function getDates()
        {
          console.log($("#date").data('datepicker').getFormattedDate('mm/yyyy'));

        }

      </script>

function addEvent(obj, evt, fn) {
    if (obj.addEventListener) {
        obj.addEventListener(evt, fn, false);
    }
    else if (obj.attachEvent) {
        obj.attachEvent("on" + evt, fn);
    }
}
addEvent(window,"load",function(e) {
    addEvent(document, "mouseout", function(e) {
        e = e ? e : window.event;
        var from = e.relatedTarget || e.toElement;
        if (!from || from.nodeName == "HTML") {
            // stop your drag event here
            // for now we can just use an alert
            alert("left window");
        }
    });
});

<?php
$json['get'] = $_GET;
$json['post'] = $_POST;
header('Content-Type: application/json');
echo json_encode($json);

var form = new FormData();
form.append("name", "value");

fetch("https://m.sg.com.ru/test.php", {
  "method": "POST",
  "headers": {
    "content-type": "multipart/form-data; boundary=---011000010111000001101001"
  }
})
.then(resp=>resp.json())
.then(response => {
  console.log(response.json());
})
.catch(err => {
  console.error(err);
});

var data = new FormData();
data.append("name", "value");

var xhr = new XMLHttpRequest();
xhr.withCredentials = true;

xhr.addEventListener("readystatechange", function () {
  if (this.readyState === this.DONE) {
    console.log(this.responseText);
  }
});

xhr.open("POST", "https://m.sg.com.ru/test.php");

xhr.send(data);