Polymer.dart binding without custom elements. In this example, we will use models.

CountNotifier.dart

class CountNotifier extends ChangeNotifier {
  int _count = 0;
  int get count => _count;
  set count(int count) {
    _count = notifyPropertyChange(#count, _count, count);
  }
}

main.dart

CountNotifier counter = new CountNotifier();

templateBind(querySelector('#counter'))
    ..model = counter;

querySelector("#inc_count").onClick.listen((_) {
  counter.count++;
});

template.html

<template id="counter" bind>
  You have clicked {{count}} times.
</template>
<input type="button" id="inc_count" value="Count">