Fire GA tags based on % of the YT video watched

gistfile1.js

var player = new YT.Player(container.find('iframe')[0]);
var firedPlay = false;
var progressFired = {25: false, 50: false, 75: false};
player.addEventListener('onStateChange', function (e) {
var duration = player.getDuration();

switch (e.data) {
    case YT.PlayerState.PLAYING:
        container.data('played', true);
        if (!firedPlay) {
            ga('send', 'event', 'video_play', 'video', 'alpargatas');
            firedPlay = true;
        }

        progressTimer = window.setInterval(function () {
            var progress = Math.round(player.getCurrentTime() / duration * 100);
            _.each(_.keys(progressFired), function (target) {
                if (Math.abs(progress - target) <= 2 && !progressFired[target]) {
                    ga('send', 'event', 'video_' + target, 'video', 'alpargatas');
                    progressFired[target] = true;
                }
            })

        }, duration / 100 * 1000);
    break;
    case YT.PlayerState.PAUSED:
        window.clearInterval(progressTimer);
    break;
    case YT.PlayerState.ENDED:
        ga('send', 'event', 'video_100', 'video', 'alpargatas');
    break;
}