var buffering = true,
    lastPlayPos,
    checkBufferIv = 50,
    element = document.createElement('video');
    element.src = "videosrc";
    element.setAttribute('webkit-playsinline', 'true');
    element.crossOrigin = "Anonymous";
    element.setAttribute('playsinline', 'true');
    element.addEventListener('canplaythrough',function(){
        buffering = false;
        setInterval(checkBuffering,checkBufferIv);
    });
    element.addEventListener('error', function(){}/*handles error*/);

function checkBuffering() {
        // checking offset, e.g. 1 / 50ms = 0.02
        var offset = 1 / checkBufferIv

        // if no buffering is currently detected,
        // and the position does not seem to increase
        // and the player isn't manually paused...
        if (!buffering &&
            element.currentTime < (lastPlayPos + offset) &&
            Player.getState() === 2){
            buffering = true;
        }

        // if we were buffering but the player has advanced,
        // then there is no buffering
        if (buffering &&
            element.currentTime >= (lastPlayPos + offset)){
            buffering = false;
        }
        lastPlayPos = element.currentTime;
    }