用JQuery撤除radiobutton的选中状态

<input type="radio" name="gender" value="M" />Male<br />
<input type="radio" name="gender" value="F" />Female<br />
<input type='button' value='Reset' id='reset' onclick='cancel()'>

<script type='text/javascript'>
????cancel=function(){
????????$('input[name=gender]:checked').attr('checked',false);
????};
</script>