mouseup event on document.documentElement does not fire with alert

Question

I need to detect mouseup event after mousedown on the document.

I have tried to add an event listener to document and document.documentElement with no success.

I need possibly a cross platform solution without jquery. Notes: problem appears on not all browsers using alert().

http://jsfiddle.net/0f7vrzh7/8/

document.documentElement.addEventListener('mousedown', function(){
alert('mousedown');
});

document.documentElement.addEventListener('mouseup', function(e){
alert('mouseup')
});

Answer 1

In certain browsers the first alert would stop the second event. It works even with alert in IE11 for example. In the browsers where you experience this issue the alert box blocks the UI before the mouseup event is processed or propagated to the element you have the event handler attached to. Change to console.log() statements in your event handlers and the events are fired as you expect them to. Updated fiddle.