Compact Inspector detects if Internet Explorer platform changes affect your site, according to the IE Blog post IE10 Compat Inspector. Compat Inspector was developed during the course of IE9 to speed up the process of recognizing common issues across different sites and have now updated it for IE10.
Compat Inspector is now available for IE10.
Whether you're preparing for IE10 or still updating for IE9, run Compat Inspector on any page experiencing problems. Then watch for messages explaining potential issues and steps you can take to resolve them.
About Compat Inspector
Compat Inspector is designed to help sites migrating to IE9 or IE10 mode—not those running in legacy modes. You can test sites that run in legacy modes by selecting a more recent mode via the F12 developer tools. Just press F12 to open the tools, click on "Document Mode" in the menu bar, then select "Standards".
The blog post describes how to get Compat Inspector and how you can use it.
Bruce D. Kyle
ISV Architect Evangelist | Microsoft Corporation