Try out different versions of Squeak in a browser (Chrome / Chromium preferred) without installing anything (JavaScript virtual machine).
Note that the versions covered are older and that the evaluation is not the full speed as you get with the downloaded version which has the Squeak virtual machine.
Copy/paste of text is possible with ctrl-c / ctrl-v
It does not work with the Squeak menu because of a browser security feature.
JavaScript cannot access the system clipboard at all times. It only works inside the browser's own copy/paste event handler, which is why it must be triggered using the browser's keyboard shortcuts or menu, not Squeak's.