Enable Disable TextBox on RadioButton click using JavaScript in ASP.Net

<div>
    <asp:RadioButton ID="RadioButton1" runat="server" Text="Yes" GroupName="Radio" onclick="Radio_Click()" />
    <asp:RadioButton ID="RadioButton2" runat="server" Text="No" GroupName="Radio" onclick="Radio_Click()" />
    <br />
    <asp:TextBox ID="TextBox1" runat="server" Enabled="false"></asp:TextBox>
    <script type="text/javascript">
        function Radio_Click() {
            var radio1 = document.getElementById("<%=RadioButton1.ClientID %>");
            var textBox = document.getElementById("<%=TextBox1.ClientID %>");
            if (!radio1.checked) {
                textBox.value = '';
                textBox.disabled = true;
            } else {
                textBox.disabled = false;
                textBox.focus();
            }
        }
    </script>
</div>