Hola
3pies
A ver si te he entendido bien:
Código PHP:
<body onload = "document.forms[0]['txt'].disabled = document.forms[0]['r1'][0].checked">
<form>
<input type="radio" name="r1" />
<input type="radio" name="r1" />
<input type="radio" name="r1" />
<input type="text" name="txt" disabled="disabled" />
</form>
Saludos,
