<!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>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>

<body>

<form name="myform" action="#">
<input type="radio" name="cb" onchange="start();" />
<input type="radio" name="cb" onchange="chgtx1();" />
<input type="text" length="10" name="tx" />
<input type="text2" length="10" name="tx1" />
</form>
<script>
function start() {
myform.tx.disabled = false;
myform.tx1.disabled = false;
}
onload = start;

function chgtx1() {
myform.tx.disabled = !myform.cb.checked;
}
</script>

</body>
</html>
