input radio只点击选择一次

<ul>
<div class="ss"><input type="radio" name="radio" class="fc" id="radio" value="a" />fdfd</div>
<div class="ss"><input type="radio" name="radio" class="fc" id="radio" value="b" />qqqq</div>
<div class="ss"><input type="radio" name="radio" class="fc" id="radio" value="c" />wwww</div>
</ul>


<script type="text/javascript">
var isTF;
$('.ss').click(function(){
isTF = $(this).siblings().find('input[type="radio"]:checked').is(":checked");
if (isTF == true) {
$(this).find("input[type=radio]").attr('checked',false);
}else{
$(this).find("input[type=radio]").attr('checked',true);
}
});
</script>