Tk in Javascript is a work in progress by apw, which started about May 2011 and is part of the incr Tcl in Javascript project.
It is intended to be one possible frontend/client part of ATWF and Reporting Tools with Tcl.
It tries to implement Tk widgets using javascript and DOM trees.
That includes a mapping of for example button/label/entry widgets to something which can be done with HTML parts in creating DOM trees and adding properties and attributes to the DOM nodes, that includes mapping of Tk option model to javascript style model and properties of DOM nodes.
Second goal is to map Tk event handling and bind functionality to the javascript event model and the javascript event listeners/handlers. There are also more complex widgets in work like Tree, Tktable, panedwindow, combobox etc.
The selection on which widgets are implemented first is driven by: what is needed for a reporting environment, that includes the decision on which options are implemented first.