<input type="radio" name="one" value="A">Operative 
 <input type="radio" name="one" value="B">Non-Operative
 <input type="radio" name="one" value="C">Both
</div>

Above radio buttons are disabled on form load, I was trying to enable first radio button with value A in console with below code which doesn't seem to work

document.getElementsByClassName("one")[0].disabled =false;