Thanks for the explanation, Herwig.
I've tried to read up on (nested) browsing contexts stuff.
The best I found so far is
"http://www.whatwg.org/specs/web-apps/current-work/multipage/browsers.html#nested-browsing-context";
… which is still pretty dense - if anyone has a pointer to a more practica
The page in the iframe contains the REPL implementation for the browser.
It's compiled and optimized with its dependencies.
Therefore the client runs in its own window object, isolated from problems
including global identifiers, modified prototypes, differing library
versions and compilation modes.
