Datepicker so MinDate i MaxDate

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="jquery_ui.css">
    <script src="jquery.js"></script>
    <script src="jquery-ui.js"></script>
    <link rel="stylesheet" href="style.css">
</head>
<body>

<p>Start Date: </p>
<input type="text" id="start_date">
<br>
<p>End Date: </p>
<input type="text" id="end_date">
<br>
<script src="main.js"></script>
</body>
</html>


$(document).ready(function (){

    $(function ()
    {
        $("#start_date").datepicker({});
    });

    $(function (){
       $("#end_date").datepicker({});
    });

    $("#start_date").change(function (){
        startDate=$(this).datepicker('getDate');
        $("#end_date").datepicker("option" , "minDate" , startDate);
    })

    $("#end_date").change(function (){
        endDate=$(this).datepicker('getDate' , "maxDate" , endDate);
    })
})