I have been making web pages for about 2 years. However, I’m trying to improve on making my pages more cross-browser friendly. I’m not sure if I can still install older versions of some browsers (namely IE and FF) on my system. Is there a program which I can open my web page code in it and have it display how it looks in various browsers (not something like Browsershots, rather something that makes the site fully interactive)? Or should I just go with something like VirtualBox?
Yes, go with Virtualbox, or, if you have some money, VMWare Fusion (assuming you are on a Mac).
Google for IETester, and then test pages in all versions of IE at once.
It hangs up occasionally, but is a lot easier than installing multiple virtual machines.
I looked into a few and thought spoon.net was brilliant Browsers on Spoon it has a load of different versions for different browsers that all work great. When I last used it they didn’t have an IE version so I used IEtester but it looks like spoon.net has now got some kind of IE set up as well but can’t really comment on it.
The site is also pretty good for some other applications such as notepad++ and filezilla which is great if you are at a computer where you don’t have either the software or the admin rights to download the software (which is what happens to me at work).
Hope thgis helps
To be honest, I wouldn’t worry about testing in older versions of anything other than IE. Other browsers have sussed out the auto-update feature much better, and most people using other browsers are the sort of people who will be quick to upgrade anyway. So there are only tiny numbers of people using older versions of Firefox, Opera, Safari, Chrome, etc.