Can I get away with testing sites using IE8 with IE7 compatibility on?

Question

As a developer, can I safely upgrade to IE8 and use its IE7 compatibility mode to test how sites look in IE7? For IE6, I have a virtual machine and it is quite inconvenient. I don't want to upgrade to IE8 and then have another virtual machine now for IE7.

Or is IE7 compatibility mode really different and I can't rely on that?

Answer 1

The MSHTML code changed. IE7 compat mode should be pretty damn close to IE7, but... the code changed. I would still test both.

Microsoft makes Virtual PC images available for testing this.

Answer 2

I use IE7 compatibility mode and it serves me all right. Did you try Multiple IE http://tredosoft.com/Multiple_IE instead of using a virtual machine?

Answer 3

I know for a fact that IE7 and IE8 (compatibility mode) are not the same. In my case it was CSS problem that showed up in IE7 and not in IE8

Answer 4

Compatibility mode in IE8 is not a 100% emulation of IE7. Security changes were not versioned, and some DOM operations were not versioned. Check out this blog post form Microsoft for a list of changes.

http://blogs.msdn.com/ie/archive/2009/03/12/site-compatibility-and-ie8.aspx

Answer 5

Microsoft is developing a tool called Expression Web SuperPreview to make it easier to test for the growing fauna of browsers.

Blog entries describing it by Long Zheng and The Expression Web Team.

Answer 6

You should try using IE Tester - a life saver. It lets you view a website on IE 5.5, 6, 7, current installed version, and 8 beta all in one program - each browser version loads in it's own tab and can be split screen etc.

Answer 7

Don't forget IETab for Firefox... making things that little bit easier. Though IIRC, you can only use this to test the version that's default on your system.

Answer 8

Seems that Microsoft has finally released Expression Web SuperPreview

It can be downloaded here

http://www.microsoft.com/downloads/details.aspx?FamilyID=8e6ac106-525d-45d0-84db-dccff3fae677&displaylang=en

Answer 9

Multiple IEs was listed in another answer.

There's a successor to "Multiple IEs" called Internet Explorer Collection that is more up to date.