Javascript formular sa datumima

Code:
<html>
    <head>
        <script type='text/javascript'>
            function promeni(obj)
            {
                
            var b=document.forma.pocetak.value;
            var c=document.forma.kraj.value;
            var d=new Date(b);
            
            document.forma.kraj.disabled=false;
            
            var datum=d.getDate();
            
            var datumPodaci=obj.value.split("-");
        /*var godina=datumPodaci[0];
        var mesec=datumPodaci[1];
        var dan=datumPodaci[2];
document.write(dan, mesec, godina);    */
            var noviDan=parseInt(datumPodaci[2])+1;
            document.forma.kraj.min=datumPodaci[0]+"-"+datumPodaci[1]+"-"+noviDan; 
            
        
            }
            
        function prikaz()
        {
            var a=document.forma.ime.value;
            var b=document.forma.pocetak.value;
            var c=document.forma.kraj.value;
            
            document.write("Ime je: "+a+"<br>");
            document.write("Datum pocetni je: "+b+"<br>");
            document.write("Datum krajni je: "+c+"<br>");
        }
        </script>
    </head>
    <body>
    
        <form name='forma' action='seminarski.html'>
            Unesi ime: <input type='text' name='ime' id='ime'><br>
            Odaberi pocetni datum:
            <input type='date' name='pocetak' id='pocetak' min='2000-01-01' onchange='promeni(this)'><br>
            Odaberi krajnji datum: 
            <input type='date' name='kraj' id='kraj' max="2020-12-31"  disabled>
            <br>
            <input type='button' name='dugme' value='klinki' onclick='prikaz()'>
        </form>
    
    </body>

</html>

Code:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><title></title>
<link rel="stylesheet" href="http://ajax.googleapis.com/aja....8.5/themes/base/jquery-ui.css" type="text/css" media="all" />
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.3/jquery.min.js" type="text/javascript"></script>
<script src="http://ajax.googleapis.com/aja...queryui/1.8.5/jquery-ui.min.js" type="text/javascript"></script>
    <script type="text/javascript">
        $(function () {

            var Datum_Start = $('#Datum_Start');
            var Datum_Kraj = $('#Datum_Kraj');

            Datum_Start.datepicker({ onClose: clearEndDate });
            Datum_Kraj.datepicker({ beforeShow: setMinDateForEndDate });

            function setMinDateForEndDate() {
                var d = Datum_Start.datepicker('getDate');
                if (d) return { minDate: d }
            }

            function clearEndDate(dateText, inst) {
                Datum_Kraj.val('');
            }
        });
    </script>
</head>
<body>
    <form name="form1" method="post" action="" id="form1">
        <input name="Datum_Start" type="text" id="Datum_Start" />
        <input name="Datum_Kraj"  type="text" id="Datum_Kraj" />
    </form>
</body>
</html>