Thanks Des,

Those two links are handy ones for AJAX heads and the the advice on eval is sound. Just because you can use it does not mean you should. It can be really great (as in the AJAX example) but it should be used with caution.

As for Multiple Inheritance, my experience has been that in general the real world we are trying to model tends to be hierarchical in a simple way so naturally modeling it will also generally result in simple inheritance trees and hence you don't need multiple inheritance often but there are good real world applications for it.

So far I think I've used it twice in real world code. Both times for doing very complex wizard interfaces in JS. I'm trying to remember the exact details but it basically involved GUI elements that were a combination of two other GUI elements. I think one of them was a submenu inheriting from menu item and from menu or something like that. Multiple Inheritance is not needed in many situations but when it is needed it saves you from code duplication which is an evil I try to avoid.