To showcase them, Codenvy is a very nice solution. It is an Online IDE that has a very nice feature called Codenvy Factory. This one lets you share the actual state of your workspace by distributing a simple link. People clicking on the click will get a copy of your workspace and can work in their own sandbox. No worries, the original workspace is not touched, so it is ideal for teaching purposes.
To demonstrate its versatility, I just made a workspace containing all ExtJS 4.2.1 examples for you to play around with.
Just click the link below and you can run all ExtJS examples and edit them as you wish online. And you even don’t have to sign up or login:
If you encounter any problems running the examples, please let me know – I already did some modifications to the original, so they are running under Codenvy.