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Internet Explorer Testing Done Right

Published by Chris Coyier

Here is the deal: you gotta test in IE. You don't have to use it, you don't have to like it, but you have to test in it. But which version do you test in? A normal windows configuration only allows a single installation of Internet Explorer. So if you are the good little downloader that Microsoft wants you to be, you are running IE 7. The problem is that IE 7 isn't nearly as awful as the previous versions, so it doesn't make an ideal candidate for a testing environment. The more bugs you find and fix, the better.

In my opinion, if you have to choose, do your testing in IE 6. IE 5.x is a dying fast and it shares many of it's oddities and bugs with IE 6.

But I'm on a Mac! Good for you, me too, but that doesn't skirt our responsibility to do serious IE testing. If you have an Intel Mac, you are in luck. I whole-heartedly suggest getting yourself a copy of Parallels. Parallels allows you to run Windows right from within OS X without rebooting. I have chosen Parallels as a sponsor for this blog for this very reason.

Run Windows on Mac OS X with no reboot!

Here is the good news: you don't have to pick a version, you can test in all versions of IE! Check out the Multiple IE Installer. This software allows you to install all kinds of versions of Internet Explorer for testing.


Now that's Internet Explorer testing! They do have a warning up saying that some version of IE running under this software are subject to random crashing. Not great, but really a small price to pay for such a great tool.

Thanks to CSSVault for making me aware of this.


  1. John Schires
    Permalink to comment#

    A word of caution about Multiple IE, it doesn’t always render pages correctly. We had used this in the shop but found many problems (flash not working correctly, styles ignored or altered, etc).

    Simple solution: If you have XP don’t upgrade to Vista. XP has IE6 installed as it’s default. If you want to switch between 6 & 7 it’s a simple matter of installing/uninstalling the IE7 upgrade. The few minutes this takes is worth it.

  2. Thanks for the cautionary tip, and the suggestion John!

    That is a great point about switching back and forth between IE 6 and 7. It doesn’t take as long as you might think, because simply uninstalling IE 7 will leave IE 6 behind.

  3. Permalink to comment#

    Conditional comments won’t work as expected when using Multiple IE. They will always default to the most current version of IE you are running under the multiple install. Meaning… if you run IE6 and IE7 (under the Multiple IE) and you are trying to use conditional comments to filter styles just for IE6, the conditional comments will not work correctly.

  4. Permalink to comment#

    Re the conditional comments problem, they have a note about that on Multiple IE’s homepage:

    by removing the “IE” key in the registry subkey [HKLM\SOFTWARE\Microsoft\Internet Explorer\Version Vector] Internet Explore defaulted to respecting conditional comments based on the version number prebuilt in the program.

    I’ve never had a problem with conditional comments after following these instructions.

    Also, Parallels is good, but I’ve had more luck with VMware Fusion. In my experience it out-performs Parallels, and allows my Macbook Pro to run plenty of other programs at the same time.

  5. Thanks for noticing that fix Dan!

    Also, I’ve heard great things about VMware Fusion. My choice of Parallels was just because that was the first one I tried and it works and it works well. I’d like to try out VMware someday if the situation arises, but in the meantime I still strongly endorse Parallels =)

  6. I personal would just use the Multiple IE tool bar and just keep either IE6 or 7. Installing the others is pointless…

    However if you have separate computers (most web geeks do), have both full proper versions.

  7. Glen
    Permalink to comment#

    I agree. VM ware fusion is really great. I have Vista on bootcamp (which can be run via VMware too) and XP, but I do all of my IE testing in XP (Vmware), where I run a standalone version of IE6 (make sure to adjust your registry to enable conditional comments) and the normal version of IE7 (I don’t test lower than IE6 anymore). Good article Chris!

  8. Man, that is just gobbledygook to me:

    registry subkey [HKLM\SOFTWARE\Microsoft\Internet Explorer\Version Vector]

    Rather than uninstalling and reinstalling software, why don’t you just delete the conditional comment while you are testing? Eg if you have an ie6 stylesheet hidden by a conditional comment, delete the cond. comment. Easy enough to put that back in.

    I use a powermac to design in, test in Safari, Firefox, Netscape. Once they’re right I have an Intel Macbook Pro by my side, load up Windows XP in Bootcamp, open IE6 in Multiple IE and type in the URL. Just need to keep uploading the stylesheet (and/or html page) to the server is about the biggest hassle. (Oh,… and searching forums to work out why the hell it won’t behave in IE6).

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