How to check if a visitor is using the latest version of his/her browser?

Question

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

Answer 1

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.

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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.