How do I install IE 7 after having already installed IE 8?

Question

I would prefer to have 8 & 7 at the same time, but it is not necessary.

The purpose is for web development testing. Not HTML and layout as that is handled through browser mode, but I want to test JavaScript.

Answer 1

Read this article to have IE6, 7 and IE8 running on Windows Vista, all at the same time!

http://www.vincecutting.co.uk/running-ie6-ie7-and-ie8-on-the-same-pc-even-on-vista.html

Answer 2

It is not possible to have both browsers installed on the same machine, unless you go with a virtual machine.

EDIT:

Or try IETester.