youtube-zoom.bookmarklet.js

(function() {

	var _x, _y;

	function scroll(video) {
		var x = _x / innerWidth;
		var dx = 1.1 * (-innerWidth/2*x + innerWidth/4);
		video.style.marginLeft = Math.round(Math.max(-innerWidth/4, Math.min(innerWidth/4, dx))) + 'px';

		var y = _y / innerHeight;
		var dy = 1.3 * (-innerHeight/2*y + innerHeight/4);
		video.style.marginTop = Math.round(dy) + 'px';
	}

	document.addEventListener('keydown', function(e) {
		if ( e.keyCode == 90 ) {
			var video = document.querySelector(':-webkit-full-screen video');
			if ( video ) {
				var zoom = video.classList.toggle('zoom15');
				if ( zoom ) {
					scroll(video);
				}
				else {
					video.style.marginLeft = video.style.marginTop = '';
				}
			}
		}
	});

	document.addEventListener('mousemove', function(e) {
		_x = e.x, _y = e.y;

		var video = document.querySelector(':-webkit-full-screen video.zoom15');
		if ( video ) {
			scroll(video);
		}
	});

})();
void(0);