So I'd download IE for Mac
I wouldn't. IE for the Mac hasn't been updated since 2003, which is ages for software and the internet, which frankly would be way outdated in terms of what it supports. His best bet would be to download either Opera or Firefox. I suspect it's something to do with the way Safari parses Javascript.
Well, I'd download whatever is the "standard" browser for Mac. Ones like Opera and Firefox aren't widely supported (though the current version of Opera for PC has no issues with Wiki/a sites.)
That was the "diagnostic tool" I was going for. Get something that you
know works and should work no matter what. I've no idea what the "standard" browser is for Mac, I just assumed they got the latest IE versions like PC does. If not, I'm sure there's got to be an Apple equivalent. Without going with a browser that may also have issues. You need a good, solid, "control." That "control" being whatever is the base of what is required or supported. Browsers like Opera or Firefox, etc. --unfortunately-- aren't the standard.