.floor_fold_bar button {
    position: relative;
    width: 110px;
    height: 38px;
    line-height: 36px;
    display: block;
    background: #2f8fd0;
    color: #fff!important;
    border-radius: 4px;
    margin: 10px auto 0 auto;
    text-align: center;
    cursor: pointer;
    border: 0;
    padding: 0;
    font-size: 14px;
    text-shadow: 0 0 black;
}
.open{
    position: absolute;
    background: #2f8fd0;
    bottom: 0;
    right: 48px;
    width: 0;
    height: 0;
    border-width: 6px 6px 4px;
    border-style: solid;
    border-color: #ffffff transparent transparent transparent;
}
.close{
position: absolute;
    background: #2f8fd0;
    top: 0;
    right: 48px;
    width: 0;
    height: 0;
    border-width: 4px 6px 6px;
    border-style: solid;
    border-color: transparent transparent #ffffff transparent;
}

<button data-floorid="0">展开超出内容<div class="open"></div></button>
<button data-floorid="0">折叠超出内容<div class="close"></div></button>

代码多， 欢迎使用复制插件。
https://hu60.cn/q.php/bbs.topic.98510.html
白日梦还是要做的