<!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 runat="server">
    <script type="text/javascript">
        function MakeItUpper()
        {
            newText = document.getElementById("TextBox1").value.toUpperCase();
            document.getElementById("TextBox1").value = newText;
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">
        <div>
            <input type="button" id="Button1" value="Duże litery"
                onclick="javascript:MakeItUpper()" />
            <input type="text" id="TextBox1" runat="server"/>
        </div>
    </form>
</body>
</html>
