Title says it all.
With Dangerous available for iDevices, it makes sense to have the chat working on those as well, which means without Flash.

You need flash to read the forums?

I'm looking at the dangerous forums on an iPad right now.

Not the forum threads, those work fine without Flash.
The chat function: In the top line, where it says "welcome, " . Below that I see "who is chatting now". Click on chatting, and you will go here:
whoisdangerous.com . . .
The page then says you need Flash Player 6 , which is a *bit* outdated anyways.

Flash 6 is outdated, but not flash . . . I'm assuming that means 6 is a minimum requirement, though.

Still, a chatroom is going to be difficult to make web-friendly for phones except maybe through javascript, and even that would be shaky.

Not an expert on that, as I am no programmer/webdesigner.
Let me check with our developers at work, maybe someone has a good idea.

I've looked into flash, macromedia, etc. Most of those browsers on mobile devices are 'streaming browsers' which give you a visual link to your browser at home. Haven't found a single browser supporting more than javascript, and those can be shaky, depending on the javascript app's complexity and it's compatibility with unknown browsers.

I asked my girlfriend who is a web developer, and she says Javascript+PHP+mySQL(optional), too.
A quick Google search for "chat javascript" turned up some things, with the link below being the best result:
sixrevisions.com . . .
Take a look at number 3 and 7 in the list, they sound promising and easy to implement, are free, and only use HTML+Javascript.

By the way, I tried the chat from my computer today, and the server did not respond. If it does not work anymore, maybe you should remove it from the menu.