Jquery利用is(“:checked”)判断单选框是不是被选中

<label class="layui-form-label" style="width:120px">性别：</label>
<div class="layui-input-block">
<input tabindex="3" type="radio" id="userSexMen" name="userSex" value="0" title="radioSex"> <label>男 </label>
<input tabindex="3" type="radio" id="userSexWomen" name="userSex" value="1" title="radioSex"> <label>女 </label>
</div>

$(".submitBtn").click(function(){

var sex = "";

$.each($("input[name='userSex']"),function(i,n){//参数i为遍历索引值，n为当前的遍历对象.
if($(this).is(":checked")){
sex = $(this).val();
}

});

}