How to do cross browser check of Ajax

There is a web site which provides contents like past browser archive.
http://browsers.evolt.org/
In this archive, there are some past browsers.
IE6 is also here.

It is unclear who has the right of them, but it is useful for one who somehow try to use other browser.

* How to run IE6 and IE7 together.
IE6 is in the category IE - 32bit - Standalone.
Download [ie6eolas_nt.zip] from http://browsers.evolt.org/?ie/32bit/standalone
,unfold it and start [iexplore.exe].