radiobutton

[jackson666]

<input type="radio" name="rbnradio1" value="si" onclick="valida(this.value);">si
<input type="radio" name="rbnradio2" value="no" onclick="valida(this.value);">no

Y tu funcion:

Código HTML:

<script language='javascript'>
function valida(val){

    if(val=='si'){
        document.getElementById("tuInput").disabled=true;
    }else if(val=='no'){
        document.getElementById("tuOtroInput").disabled=true;
    }

}
</script>