A most complex gtag app (with interaction) could look like this

from gtag import GTag, Tag

class Comp(GTag):
    size=(200,100)
    def build(self):
        return Tag.div(
            Tag.span( "hello world" ),
            Tag.button( "Click me", onclick=self.bind.clickMe() ),
        )
    def clickMe(self):
        print("You have clicked")

app=Comp()
app.run()

Important

• self.bind.clickMe() is the way to bind the interaction with the self.clickMe(). (It will produce a js statement for the onclick event)
• self.clickMe() is an event. At each call, it will update the rendering.
• the build() method is called at each rendering time.