How can I chage a textbox visibility false on radiobuttonlist item checkchange using javascript

hello experts
Me with C# asp.net, I have a text box and a radiobuttonlist in one of my forms with two radiobutton list items 1 and 2 When I click the first radio button in the list ie 1 the text box should not be shown and when I click 2 the text box should be shown
How can I do it with javascrip I mean with out post back my code is


<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <table style="width: 299px">
            <tr>
                <td style="width: 113px&qu ...