Is there a lightweight library I can use to ask users to download a modern browser?

Question

I'm building a site that relies heavily on several HTML5 features. I do not want to develop a separate version of the site for IE6-8. Instead, when those users visit, I'd like a nice-looking modal to pop up to politely suggest that they visit the site with a modern browser like Chrome or Firefox. Is there an existing library that will do this for me?

Ideally, modern browsers would only have to download the browser detection code; the code powering the modal would be loaded asynchronously only when needed.

Answer 1

Try this: http://www.ie6countdown.com/join-us.aspx

Answer 2

Use Modernizr. Instead of checking what browser they use, you can check for the exact feature that you need and display an alert if the current browser does not support it. Additionally, Modernizr also includes the YepNope library which lets you conditionally load resources that you need (like the modal you mentioned)