It uses pas2js as the compiler, together with its basic RTL, inside Delphi.
This is a commercial product which allows you to design your web page as you
would design a Delphi application, using the Delphi form designer.
It comes with a full set of widgets (components), based on their FNC components.
But they also provide a wrapper around a large set of jQuery components, jqWidgets.
The plan is that later on they will release a Lazarus version of their product.
Of course, it would be nice if the lazarus community would attempt to make a
LCL widgetset using pas2js... I think TMS Software has shown in a convincing
manner that pas2js is up to the task...