Is there a simple and automatic way of checking if a visitor to my website (written in asp.net) is using the latest version of his browser? This would allow me to display a message to inform them that they're running an old version and that they might want to upgrade.
My website is tested on most broswers but I don't test old versions (such as Internet Explorer 6 etc). When one of my visitors is using such an old version, basically, I would like to encourage (not force) them to upgrade.
Of course I could do this myself by getting the version of the browser and look it up in my database but I don't want to have to maintain a 'browser version' database myself. Any ideas?
Speaking as a user of websites, if I come across a site that advised me to upgrade my browser then that would be an immediate black mark against that site.
I might not be able to upgrade (if I'm accessing from a corporate network for example); I might have a specific reason for using a particular version (if I'm a web developer wanting to ensure compatibility with my user community for example).
So personally, I would say that a blanket disclaimer that you don't test this site on earlier versions would be the way to go. That's quite apart from the technical challenge of what you want to do.
Edit: as Yeti points out, however valid my concerns, I don't answer the question directly. This is done in Pace's answer, and the w3schools resource he points to gives you what you need to do this on the client side.
来源：https://stackoverflow.com/questions/720826/how-to-check-if-a-visitor-is-using-the-latest-version-of-his-her-browser