var numberInput := displayNewElementIn('', 'body', 'input', false)
numberInput.value := 0
var incButton := displayNewElementIn('Increment', 'body', 'button', false)
var rndButton := displayNewElementIn('Random', 'body', 'button', false)

parallel:
	while true:
		awaitDomeventBeep('change', numberInput)
		if not (0+1*numberInput.value = 0+1*numberInput.value):
			displayNewMessage('Invalid input !')
	while true:
		awaitClickBeep(incButton)
		numberInput.value := 1*numberInput.value + 1
	while true:
		awaitClickBeep(rndButton)
		var msg := displayNewMessage('Are you sure?<button id="yes">Yes</button><button id="no">No</button>')
		parallel(select 1) ||
		||=========
			awaitClickBeep('#yes')
		...--------
			numberInput.value := randomIntBetween(0, 5000)
		||=========
			awaitClickBeep('#no')
		...--------
			displayNewMessage('No problem!')
		removeElt(msg)