onSelect function of jquery datepicker is not working

Question

<label class="label-size"  for="location">Select Date&nbsp;<sup style="color:#e7377b"class="label-size">*</sup></label>
<input type="text" id="datefield1" class="form-control resDate" name="pickup_date" readonly autocomplete="off" required>


$("#datefield1").datepicker({
    onSelect: function (date, datepicker) {
                if (date != "") {
                    alert("Selected Date: " + date);
                    console.log("working");
              //This alert is just for check otherwise I have to show delivery time of specific day and location [here I wanna use this code](https://i.stack.imgur.com/wK4l8.png)
                }
            }
        });`

I tried almost all possible ways but none of them are working ; I am expecting that on Select the date I can show availability of delivery time on that day.