Strange HTTP_USER_AGENT for IE8 in PHP

How is that possible?

http://img191.imageshack.us/img191/7080/wtfsg.开发者_开发知识库jpg

Any solution to separate IE8 from IE7?

To quote this article on IEBlog:

IE8 will send the “MSIE 7.0” version information when viewing sites with Compatibility View enabled. (...) A new “Trident” token in the User-Agent string allows your code to detect Internet Explorer 8 clients even when they are using the Compatibility View feature.

To wit, your page is displayed in Compatibility mode, hence the UA change.

In this case you need to check from your developer toolbar if you are rendering your site as IE7.

You can get to the developers toobar by hiting F12 and checking the browser mode and puting it to IE 8.