How to pass date from datepicker to php

The code you pasted into the snippet contains errors that may cause it to malfunction - e.g. unclosed form tag:

<div class="col-md-3">
  <div class="form-outline datepicker">
    <input type="text" class="form-control" id="exampleDatepicker1" name="date1" data-toggle="datepicker" value="Start Date" />
    <label for="exampleDatepicker1" class="form-label">Date</label>
  </div>
  <form action="reservations_per_day.php" method="post">
</div>

and commented out variable:

<! - Variable format for html doc
$ var_value = $ _SESSION ['varname'];
 ->

There is no special method to get value from the datepicker. The datepicker will contain the input from which you just need to get value. Do you have any errors in the console after selecting start date and end date?

Thanks for getting back with me. I have added the closing form tag to my code (not the snippet). Where do I init the datepicker though and choose options? So If I would like to set the default date? Example:

$(document).ready(function({
    $('#textboxname').datepicker();
    $('#textboxname').datepicker('setDate', 'today');
});

It can stay in the same place as it is added in the snippet. You also don't need to initialize the timepicker first and set options later. You can set options right on initialization.