When it comes to cross-browser compatibility, no browser causes more pain and suffering than Internet Explorer—no version is as standards-compliant as Firefox, Opera, or Safari, and every version has its own unique bugs and issues. The majority of CSS hacks, testing, and workarounds are for Internet Explorer. Testing has been a major pain, requiring a different computer or meddling with the registry for each version of IE.

Finally, Test IE7, IE6, IE5, IE4, and IE3 in Parallel

Yousif Al Saif built upon some others’ work to create an installation for each of the major versions of Internet Explorer since IE3. Read about it here, and download the multiple IE installer here.

Power Testing

The truth is, almost no one still uses IE 3 and IE 4, and very few people use IE 5. Most of your testing will involve IE 6 and IE 7, with an occasional nod to IE 5.5.

I installed IE 5.5, IE 6, and IE 7 on my machine. Everything is working fine, without any crashes, hanging, or strange behavior.

Testing is powerful and easy—I can open all the versions I want to test at the same time. I make a change and then hit Alt-Tab to switch through all the browsers on my machine—Firefox, Opera, and IE 5-7, thus covering about 95% of all the browser users out there and catching nearly all known (and still important) cross-browser issues.

I just need a Mac so I can test small changes on Safari (For final testing on a Mac (not incremental), see my post about testing on Safari).