求救！怎样单击其它地方将单选按钮选中？

Question

<label for="r2"><input type="radio" id="r2" name="rkey" value="2">正确答案</label>或者<td onclick="r1.checked=1"><input type="radio" name="r1" value="radiobutton">aaaaa</td>

Answer 1

<table width="75%" border="1">
    <tr>
      <td onclick="r1.checked=r1.checked?false:true"><input type="radio" name="r1" value="radiobutton">aaaaa</td>
    </tr>
</table>

Answer 2

能否用一个函数，如IsSelect()来解决？

Answer 3

<td onclick="IsSelect()"><input type="radio" name="r1" value="radiobutton">aaaaa</td>
这个不就是函数么？非要写成function也行
<td onclick="r1.checked=1"><input type="radio" name="r1" value="radiobutton">aaaaa</td>
<script>
function IsSelect()()
{r1.checked=!r1.checked}
</script>

Answer 4

<table width="75%" border="1">
    <tr>
      <td onclick="IsSelect(r1)"><input type="radio" name="r1" value="radiobutton">aaaaa</td>
    </tr>
</table>
<script>
function IsSelect(r){
r.checked=r.checked?false:true;
}
</script>