“tap” event is executed twice

[satrong]

When I add <meta name="viewport" content="width=device-width, initial-scale=1.0" /> in the head, “tap” event is executed twice on andriod 5.1.1/chrome 49.0.2623.91.

dom.addEventListener("tap",function(){
    alert('will alert twice');
})

if I edit the code like blow will be OK:

dom.addEventListener("tap",function(event){
   event.preventDefault();
    alert('will alert once');
})

it was a tap's BUG or my fault?

[tracid]

Same Problem on all Apple mobile devices in Chrome/Safari... I use delegated events, maybe thats the problem?

[phillnexus]

Same issue in IE11 currently

[Namek]

what is more, preventDefault() doesn't fix the issue on IE11. Neither return false does.

Note: may be related to #16 and #23.

[tmrk]

+1 to this, it's clearly a bug.

Any ideas how to solve it?

As mentioned, preventDefault() is not helping under IE.