disabilitare un pulsante da un radio button

[TrueLies]

<form>
<input type="radio" name="foo" value="1" onclick="document.getElementById('fooB').disabled= false; document.getElementById('fooA').disabled=true;" />

<input type="radio" name="foo" value="2" onclick="document.getElementById('fooA').disabled= false; document.getElementById('fooB').disabled=true;" />

<input type="button" id="fooA" value="pulsante A" />
<input type="button" id="fooB" value="pulsante B" />
</form>