Mutes a YouTube video at a specific point

mute.js

// for use on https://www.youtube.com/watch?v=e1X4RPDE-48
var video = document.querySelector('video');
var count = 0;
var interval = null;
video.ontimeupdate = function(event) {
	if (interval === null && !this.paused && this.currentTime > 175 && this.currentTime < 180) {
		console.log('start');
		count = 0;
		interval = setInterval(doIt, 40);
	}
}

function doIt() {
	if (video.paused || video.currentTime > 180) {
		console.log('end', count);
		clearInterval(interval);
		interval = null;
	}
	if (video.muted = video.currentTime >= 176.5 && video.currentTime < 177.1) {
		count++;
	}
}