底部固定js

html, body {
    height: 100%;
    margin: 0;
}

.wrapper {
    min-height: 100%;
    margin-bottom: -50px; /* 底部元素的高度 */
}

.footer, .push {
    height: 50px; /* 底部元素的高度 */
}

<div class="wrapper">
    <!-- 页面内容 -->
    <div class="push"></div>
</div>
<div class="footer">
    版权所有 &copy; 2023
</div>

function fixFooter() {
    var footer = document.querySelector('.footer');
    var wrapper = document.querySelector('.wrapper');
    var footerHeight = footer.offsetHeight;
    var windowHeight = window.innerHeight;

    if (wrapper.offsetHeight < windowHeight) {
        footer.style.position = 'fixed';
        footer.style.bottom = '0';
        wrapper.style.marginBottom = footerHeight + 'px';
    } else {
        footer.style.position = 'static';
        wrapper.style.marginBottom = '0';
    }
}

window.addEventListener('resize', fixFooter);
document.addEventListener('DOMContentLoaded', fixFooter);

.content {
    padding-bottom: 50px; /* 底部元素的高度 */
}