I am using the latest beta version of Antetype and I'm pretty excited at the perspective of this product's development. I will purchase my copy next week.
It's extremely common in web design to have one widget trigger a state change in an unrelated widget, or collection of widgets. As it stands today, Antetype allows cross-widget state change only if they can be accessed via CSS pseudo-selectors (siblings, children and so forth).
The most basic way to program this by hand is to reference the target widget by ID, which is easy even for a novice using JQuery.
In the event drop-down, along with the list of pseudo-selectors, an entry could be added for "Elements by name:" could be added, with a text field (identical to the source widget text field) in which the user may add as many target widgets as necessary.
I suspect Antetype doesn't rely on JS to perform any display operation and instead relies on pure CSS for animation and basic event management.
Never mind !
I had not understood the syntax of the event editor — I thought the event (say "Mouse Click") was tied to the named item in the field just below it. As it stands, the event is implicitly tied to the widget that the event is declared for. I think you should name the widget in the event panel nonetheless, such that the syntax is clear. Source and targets should be clearly stated.
I am glad you figured it out. We are currently working on an improved interaction system which gives more flexibility in this regard. You can take a peek in our beta for version 2.
And for your first post: Antetype currently doesn't use HTML/CSS, even the web viewer paints the screen into a big canvas.