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HTML

<html xmlns="http://www.w3.org/1999/xhtml">
    <head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <title>Display Date and Time in Javascript</title>
        <script type="text/javascript" src="date_time.js"></script>
    </head>
    <body>
            <span id="date_time"></span> <script type="text/javascript">window.onload = date_time('date_time');</script>
    </body>
</html>

JavaScript

function date_time(id)
{
    alert('jjj');
        date = new Date;
        year = date.getFullYear();
        month = date.getMonth();
        months = new Array('January', 'February', 'March', 'April', 'May', 'June', 'Jully', 'August', 'September', 'October', 'November', 'December');
        d = date.getDate();
        day = date.getDay();
        days = new Array('Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday');
        h = date.getHours();
        if(h<10)
        {
                h = "0"+h;
        }
        m = date.getMinutes();
        if(m<10)
        {
                m = "0"+m;
        }
        s = date.getSeconds();
        if(s<10)
        {
                s = "0"+s;
        }
        result = ''+days[day]+' '+months[month]+' '+d+' '+year+' '+h+':'+m+':'+s;
        document.getElementById(id).innerHTML = result;
        setTimeout('date_time("'+id+'");','1000');
        return true;
}