..mobile browsers will wait approximately 300ms from the time that you tap the button to fire the click event. The reason for this is that the browser is waiting to see if you are actually performing a double tap.
(from a new defunct https://developers.google.com/mobile/articles/fast_buttons article)
touch-action CSS property can be used to disable this behaviour.
touch-action: manipulationThe user agent may consider touches that begin on the element only for the purposes of scrolling and continuous zooming. Any additional behaviors supported by auto are out of scope for this specification.