YouTube Repeater 的 UserScript 在YouTube上开启洗脑循环

userscript-YouTube-Repeater.js

// ==UserScript==
// @name        YouTube Repeater
// @namespace   ETiV
// @include     http://www.youtube.com/watch?v=*
// @version     1
// ==/UserScript==

(function(){
  var player = null, run_state = 0, repeat_state = false;
	var btnTogglePlayState = document.createElement('button');
	const HTML_PLAY = '<span>&#9654;</span>',
			HTML_PAUSE = '<span style="display:inline-block;transform:rotate(90deg);">&#12307;</span>';
	var getPlayer = function () {
		var _p = document.getElementById('movie_player');
		if (_p.getPlayerState() === 1) {
			player = _p;
			player.addEventListener('onStateChange', 'onYTStateChange');
			run_state = 1;
		}
	};
	var getDuration = function () {
		try {
			if (player) return player.getDuration();
			else return -1;
		} catch (e) {
			return -1;
		}
	};
	var getCurrentTime = function () {
		try {
			if (player) return player.getCurrentTime();
			else return -1;
		} catch (e) {
			return -1;
		}
	};
	var play = function () {
		try {
			if (player) player.playVideo();
		} catch (e) {
		}
	};
	var pause = function () {
		try {
			if (player) player.pauseVideo();
		} catch (e) {
		}
	};
	// var stop = function () {
	// 	try {
	// 		if (player) player.stopVideo();
	// 	} catch (e) {
	// 	}
	// };
	var state = function () {
		try {
			if (player) return player.getPlayerState();
			else return -1;
		} catch (e) {
			return -1;
		}
	};
	var seekTo = function (start) {
		try {
			if (player) player.seekTo(start, true);
		} catch (e) {
		}
		
	};
	var interval = setInterval(function () {
		if (run_state === 0 && player === null) {
			getPlayer();
		} else if (run_state === 1) {
			document.querySelector('#masthead-upload-button-group').style.marginRight = '5px';
			
			btnTogglePlayState.className = 'yt-uix-pager-button yt-uix-pager-show-more yt-uix-button yt-uix-button-default yt-uix-button-size-default';
			if (state() == 1) {
				btnTogglePlayState.innerHTML = HTML_PAUSE;
			}
			if (state() == 2) {
				btnTogglePlayState.innerHTML = HTML_PLAY;
			}
			document.querySelector('#masthead-upload-button-group').appendChild(btnTogglePlayState);
			btnTogglePlayState.onclick = function () {
				if (state() == 1) {
					pause();
				} else if (state() == 2) {
					play();
				}
			};

			var btnToggleRepeat = document.createElement('button');
			btnToggleRepeat.className = 'yt-uix-pager-button yt-uix-pager-show-more yt-uix-button yt-uix-button-default yt-uix-button-size-default';
			btnToggleRepeat.innerHTML = '<span style="display:inline-block;transform:rotate(90deg);">&#65304;</span>:' + (repeat_state?'ON':'OFF');
			document.querySelector('#masthead-upload-button-group').appendChild(btnToggleRepeat);
			btnToggleRepeat.onclick = function () {
				repeat_state = !repeat_state;
				btnToggleRepeat.innerHTML = '<span style="display:inline-block;transform:rotate(90deg);">&#65304;</span>:' + (repeat_state?'ON':'OFF');
				if (repeat_state === true && state() === 0) {
					play();
				}
			};
			clearInterval(interval);
		}
	}, 500);

  // NOTE : this `onYTStateChange` must be set in the global scope,
  //        because the event listener registered to youtube player need this name as string
  //        to invoke the certain event
	window['onYTStateChange'] = function(state){
		if (state === 0 && repeat_state) {
			play();
		} else {
			if (state == 1) {
				btnTogglePlayState.innerHTML = HTML_PAUSE;
			}
			if (state == 2) {
				btnTogglePlayState.innerHTML = HTML_PLAY;
			}
		}
	};
})();