Why current date and time shown via javascript not working in IE 11?

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ASP.NET

C#3.5

IE11

I am showing current date and time to a textbox via javascript. But the below code is not working in IE 11. It's working in IE 8. I set alert messages and it is coming fine in IE 8 but not in IE 11.

Current Code is as below:

<script type="text/javascript">
               var OutEnvelope = -1;
                var InEvelope = -1;
                //setInterval(function() { showStatus(); }, 5000);
        window.setTimeout("ShowTime()", 1000);
        function ShowTime() {

            var dt = new Date();
            alert(123);
            alert(document.getElementById("<%= TextBox1.ClientID %>").value);
            if(document.getElementById("<%= TextBox1.ClientID %>").value!='undefined')
            {
                document.getElementById("<%= TextBox1.ClientID %>").value = dt.toLocaleDateString() + ' ' + dt.toLocaleTimeString();

                window.setTimeout("ShowTime()", 1000);
            }

        }