The keypress event is fired when a key that produces a character value is pressed down. Open up the browser console to see that and as well the js tab.
<ch5-textinput type="text" feedbackMode="submit" value="initial value"> </ch5-textinput>
var input = document.querySelector('ch5-textinput'); input.addEventListener('keypress', function(e){ console.log('textinput keypress event: ', e); });