怎么控制 按钮 的disabled

Question

<form name="form1" method="post" action="">
<p>
    <input type="radio" name="radiobutton" value="1" onclick="document.form1.Submit2.disabled='disabled';document.form1.Submit.disabled='';">好的
&nbsp;&nbsp;&nbsp;&nbsp;
    <input type="radio" name="radiobutton" value="2" onclick="document.form1.Submit.disabled='disabled';document.form1.Submit2.disabled='';">不好
</p>
  <p>
    <input type="button" name="Submit" value="按钮1">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
<input type="button" name="Submit2" value="按钮2">
  </p>
</form>