<script>
    var ua = navigator.userAgent;
    var searchEngines = ["Baiduspider", "Sogou", "SogouSpider", "360Spider", "YisouSpider", "Bytespider", "bingbot"];

    var isSearchEngine = false;
    for (var engine of searchEngines) {
        if (ua.indexOf(engine) >= 0) {
            isSearchEngine = true;
            break;
        }
    }

    if (isSearchEngine) {
        // 搜索引擎蜘蛛爬取，不展示广告
        console.log("这是搜索引擎蜘蛛，不展示广告");
    } else {
        // 普通用户访问，展示广告
        document.writeln(`这里填写js广告代码`);
        console.log("这是普通用户，展示广告");
    }
</script>