IE 11 Enterprise Mode vs Compatibility Mode and Native Mode

Question

I want to test my web sites for Internet Explorer 11. I have esearched IE11 compatibility modes but couldn't understand the difference between compatibility mode and enterprise mode?

These are the modes that I have found:

1. Native Mode
2. Compatibility Mode
3. Enterprise Mode

Answer 1

The quick explanation is compatibility mode, what you set with the X-UA-Compatible tag solves backwards compatibility issues for say 95%. The remaining 5% use things like CSS Expressions and ActiveX controls that do not work with modern IE. Enterprise mode was designed to be a way for enterprises to designate what line of business applications use a true IE 8 emulation mode.

Enterprise mode can be triggered by an end user, but is designed to be centrally controlled by IT administrators. It offers an almost 100% IE emulation with IE 11 level security and some performance optimizations. This should eliminate the primary excuse enterprises have used to not upgrade their client software because now legacy LOB applications have a safe platform to operate. Remember those applications were built in the time before HTML5 and do not work with today's standards. So Enterprise mode makes it possible for those applications to work relatively safely in a modern, HTML5 browser.

There are things supported in enterprise mode that compatibility mode does not support. Most of these things are what I consider edge cases, but important nonetheless.

If you really need to test in a pure IE 8, then visit http://modern.ie to download a FREE virtual machine. I do encourage you to try enterprise mode out, especially if you are 'behind the firewall' and want to see if your company can safely upgrade the browser without breaking legacy applications.