关闭浏览器标签页前自定义确认弹窗实现方案咨询

我希望在用户尝试关闭标签页或窗口时，实现一个非默认JS alert样式的自定义确认弹窗。我已查阅诸多同类问题，发现旧方案中自定义弹窗文本的方式在现代浏览器中已被废弃。我现有代码可实现默认JS alert样式的弹窗，但想咨询是否有办法对其进行自定义，相关代码如下：

<!DOCTYPE html>
<html>
    <head><meta charset="utf-8"></head>
    <title>Leave Site Pop-up</title>
<body>

<h1>My First Heading</h1>

<input name="name" id="name"/>

<script type="text/javascript">
    const beforeUnloadListener = (event) => {
        event.preventDefault();
        return event.returnValue = "Are you sure you want to exit?";
    };

    const nameInput = document.querySelector("#name");

    nameInput.addEventListener("input", (event) => {
        if (event.target.value !== "") {
            addEventListener("beforeunload", beforeUnloadListener, {capture: true});
        } else {
            removeEventListener("beforeunload", beforeUnloadListener, {capture: true});
        }
    });
</script>
</body>
</html>

内容的提问来源于stack exchange，提问作者Ema