去到底部、回到顶部css当网页向下滑动 20px 出现"返回顶部" 按钮
html <div> <button onclick="returnTop()" id="btnTop" title="返回顶部">返回顶部</button> <button onclick="returnBottom()" id="btnBottom" title="去到底部">去到底部</button> </div> 样式 #btnTop { display: none; position: fixed; bottom: 20px; right: 30px; z-index: 99; border: none; outline: none; background-color: #89cff0; color: white; cursor: pointer; padding: 15px; border-radius: 10px; } #btnTop:hover { background-color: #1E90FF; } #btnBottom { display: none; position: fixed; bottom: 100px; right: 30px; z-index: 99; border: none; outline: none; background-color: #89cff0; color: white; cursor: pointer; padding: