Displays a visual warning at the top of a page when a user has 'Compatibility View' mode enabled in Internet Explorer.
This page includes the compatibilityViewWarning script. Just open this url in Internet Explorer 8, 9 or 10 and you should see something like this:
Couldn't be easier, just include compatibilityViewWarning.min.js somewhere on your page like so:
<script src="https://raw.github.com/okize/compatibilityViewWarning/master/compatibilityViewWarning.min.js">