This is just an experiment, a tech demo if you want, but is worth mentioning since it shows how flexible the Plasma scriptengine architecture is. In brief: adding the support of a new language, a new package structure to do widgets and graphics components in some cases takes literally minutes, and then is possible to load this new kind of widgets alongside the existing ones written in c++/qml/javascript/python/whatever.
Now, Plasma supported from the very beginning writing plasmoids using HTML+Javascript, and it allowed in two ways: Mac OSX dashboard widgets or a native style that lets you access the Plasma dataengines and services right within Html and JavaScript.
There is now an effort called WAC to produce a standard-ish package format and api for html widgets and simple apps.
Whether this will go somewhere or not is early to say (just usual wait and see;), but i wondered how hard could it be support loading a package in the wac format and correctly displaying it into a plasma desktop/netbook/tablet session, so this is the result of literally 30 minutes of work 😉 (TicTac toe and the todo thing are example WAC widgets, the rss feed reader is in pure QML)
This can be found in the branch plasma/mart/wac-appletscript of the kde-workspace repo, or can be directly tried built in in the Plasma Active One release (there you go, another reason to try out Plasma Active if there weren’t enough 😉
This is not going in an official near KDE Workspace release since is far from be complete. Namely, it’s lacking the device api, but since is very easy to bind extra objects to QtWebkit, is just matter to sit down and doing it (contributions, as usual are welcome ;).