Having done some intensive research over the last couple of days to define exactly what happens when you set your IE browser to Compatibility View I thought it was worth noting a few things down.
- IE uses Compatibility View to let website developers/administrators define how a website is displayed regardless of the version of IE being used. This is because MS are moving away from their bespoke CSS implementations, used for < IE7, to the more recognised W3C version.
- By default, any IE user running in the Local Intranet Security zone is automatically forced into Compatibility View. However, this option can be changed either by a user with sufficient permissions or Group Policy.
- There is no way to programmatically stop users from running the site in Compatibility View. Adding the <meta> tag correctly disables the option from the Tools menu but the site can still be forced into Compatibility View either by:
- Using the default Compatibility View settings and running in the Local Intranet security zone
- Adding the site to the Compatibility View settings (this is a separate option to the Compatibility View switch in the Tools menu).
These are some of the useful links I have found whilst scouring the web for relevant information:
- Introducing Compatibility View
- Compatibility View and “Smart Defaults”
- Defining Document Compatibility
- IE’s Compatibility Features for Developers
- Testing Sites with Browser Mode vs Doc Mode
- HTTP_EQUIV Attribute
- Determining Document Mode diagram for IE9