<div class="scroll-control">
<div id="back-to-top" class="scll-ctrl-styl">
<div class="to-top-triangle to-tri"></div>
</div>
<div id="two-dimension-code" class="scll-ctrl-styl">
<img class="two_dimension_code" src="/images/two_dimension_code_present.png" />
</div>
<div id="write-some-suggestion" class="scll-ctrl-styl">
<div class="to-bottom-triangle to-tri"></div>
</div>
</div>
如果第一个自 div 隐藏后,余下两个会跑上去?难道要每个都设置 fixed 计算好 bottom ,有没什么方法使隐藏后不会兄弟 div 占用?

