How to set default focus for a control in form in asp.net

How to set default focus for a control in form
FormDefaultFocus.aspx

<%@ Page Language="C#" %>

<!DOCTYPE html>

<script runat="server">

</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>How to set default focus for a control in form</title>
</head>
<body>
    <form id="form1" runat="server" defaultfocus="TextBox2">
    <div>
        <h2 style="color:Navy">Form defaultfocus Property</h2>
        <asp:Label 
             ID="Label1" 
             runat="server"
             Font-Bold="true"
             ForeColor="DarkGreen"
             Text="Employee Name"
             >
        </asp:Label>
        <asp:TextBox 
             ID="TextBox1"
             runat="server"
             BackColor="DarkGreen"
             >
        </asp:TextBox>
        <br />
        <asp:Label 
             ID="Label2" 
             runat="server"
             Font-Bold="true"
             ForeColor="DarkGreen"
             Text="National ID"
             >
        </asp:Label>
        <asp:TextBox 
             ID="TextBox2"
             runat="server"
             BackColor="DarkGreen"
             >
        </asp:TextBox>
        <br /><br />
        <asp:Button 
             ID="Button1" 
             runat="server"
             Font-Bold="true"
             ForeColor="DarkGreen"
             Text="Submit"
             />
    </div>
    </form>
</body>
</html>
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