How to automatically copy text from textbox as type in another textbox using JavaScript or jQuery

This way

    First Name: <asp:TextBox ID="txtFirstName" runat="server"></asp:TextBox><br />
    Last Name: <asp:TextBox ID="txtLastName" runat="server"></asp:TextBox><br /><br />
    
    Name: <asp:TextBox ID="txtName" runat="server"></asp:TextBox>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
    <script type = "text/javascript">
        $(function () {
            $("[id$=txtFirstName], [id$=txtLastName]").bind("keyup", function () {
                $("[id$=txtName]").val($("[id$=txtFirstName]").val() + ' ' + $("[id$=txtLastName]").val())
            });
        });
    </script>