Seaside (Smalltalk web framework) provides something similar to this, where you can access the Smalltalk browser (i.e. IDE & Debugger) directly in the web brows

Seaside (Smalltalk web framework) provides something similar to this, where you can access the Smalltalk browser (i.e. IDE & Debugger) directly in the web browser. Whether or not you'd actually develop this way, is another question. Unfortunately I cannot find a running example openly available on the web, probably because you could easily crash the server if you wanted to.