为什么后代选择器不起作用

Question

for(var i = 0; i < 2; i++) {

$("#activity_time"+i+" a").removeClass("buy_button");

}

<div>

<input type="hidden" name="activity_time" id="activity_time0" value="2018/4/25 16:13:59" />
<a href="#" class="buy_button"></a>

</div>
<div>

<input type="hidden" name="activity_time" id="activity_time1" value="2018/4/25 16:13:59" />
<a href="#" class="buy_button"></a>

</div>

问题：样式没有移除

Answer 1

因为a压根儿不是input的后代……人家input是个自闭合的标签啦。

---

for(var i = 0; i < 2; i++) {
    $('#activity_time' + i)
        .siblings('a')
        .removeClass('buy_button');
}

Answer 2

$("#activity_time"+i+"~ a")

CSS [attribute~=value] 选择器