radio button を非活性にする

gistfile1.txt

<input type="radio" name="disableme" id=1> Animal
<input type="radio" name="disableme" id=2> Mammal
<input type="radio" name="disableme" id=3> Human


var radios = document.formName.disableme;
for (var i=0, iLen=radios.length; i<iLen; i++) {
  radios[i].disabled = true;
}