更改消息似乎仅在Internet Explorer中有效(请参见 w3schools ).我认为您也不能插入阻塞代码(例如alert())，因为这将对浏览器造成安全漏洞.

unfortunately, changing the message seems to only work in Internet Explorer (see w3schools). I don't think you'll be able to insert blocking code either(such as alert()), as it would be a security breach for the browser).