'tap' & 'click' on buttons has different css style

hi, i find that for a same button, ‘tapping’ it (fast touch) and ‘clicking’ it (longer touch) has different css style, could you advise how can I make the ‘clicking’ behaviour acts same as ‘tapping’ behaviour? below is one of the example of my button:

<div class="button-bar">
                <a class="button button-icon button-clear ion-chatbubble-working" on-tap="popUpComment()"></a>

when i ‘click’ on the button, the button flashes once, but when i ‘tap’ on it, there’s no such problem