取消radio的选中状态

一个简单的例子，是懒宝宝让我帮忙的。因为我自己也注意到了，radio在选中后，一般无法取消，查了一下google，发现还是有方法 的。因此，立马解决了：

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.1/jquery.min.js"></script>
<table class="rs" border="0" cellspacing="0" cellpadding="0">
<tr>
<td>HIV ：阴
<input type="radio" name="hiv[0]" value="HIV:阴" union="yin"/>
阳
<input type="radio" name="hiv[0]" value="HIV:阳" union="yang" /></td>
<td>梅毒：阴
<input type="radio" name="hiv[1]" value="梅毒：阴" union="yin" />
阳
<input type="radio" name="hiv[1]" value="梅毒：阳" union="yang" /></td>
<td>疱疹：阴
<input type="radio" name="hiv[2]" value="疱疹：阴" union="yin" />
阳
<input type="radio" name="hiv[2]" value="疱疹：阳" union="yang" /></td>
<td>淋病：阴
<input type="radio" name="hiv[3]" value="淋病：阴" union="yin" />
阳
<input type="radio" name="hiv[3]" value="淋病：阳" union="yang" /></td>
</tr>
<tr>
<td>非淋：阴
<input type="radio" name="hiv[4]" value="非淋：阴" union="yin" />
阳
<input type="radio" name="hiv[4]" value="非淋：阳" union="yang" /></td>
<td>湿疣：阴
<input type="radio" name="hiv[5]" value="湿疣：阴" union="yin" />
阳
<input type="radio" name="hiv[5]" value="湿疣：阳" union="yang" /></td>
<td>丙肝：阴
<input type="radio" name="hiv[6]" value="丙肝：阴" union="yin" />
阳
<input type="radio" name="hiv[6]" value="丙肝：阳" union="yang" /></td>
<td><a style="cursor:pointer;" id='allyin'>全阴</a> <a style="cursor:pointer;" id='allyang'>全阳</a> <a id='allempty' style="cursor:pointer;">重填</a>
<script>
$(function(){
$('#allyin').click(function(){
$(':input[union="yin"]').attr('checked','checked');
});
$('#allyang').click(function(){
$(':input[union=yang]').attr('checked','checked');
});
$('#allempty').click(function(){
$(':input[union=yang]').each(function(){
$(this).attr('checked','checked');
var tmp = $(this)[0];
tmp.checked = false;
tmp = null;
})
});
});
</script></td>
</tr>
</table>