1. Add a highlighted state animation and set it to a button:

.button {
background-color: green;
}

.button:highlighted {
animation-name: highlight;
animation-duration: 2s;
animation-fill-mode: forwards;
}

@Keyframes highlight {
from { background-color: yellow; }
to { background-color: red; }
}

1. Play the animation by touching the button.
2. Touch up before the animation ends. The button will remain in some undetermined state. The correct behavior is to reset its background to green (like in iOS).